Exhibit 5

SIMPSON THACHER & BARTLETT LLP

425 LEXINGTON AVENUE

NEW YORK, N.Y. 10017-3954

(212) 455-2000

FACSIMILE (212) 455-2502

March 4, 2020

Cigna Corporation

900 Cottage Grove Road

Bloomfield, Connecticut 06002

Ladies and Gentlemen:

We have acted as counsel to Cigna Corporation, a Delaware corporation (the “Company”), in connection with the Registration Statement on Form S-3 (the “Registration Statement”) filed by the Company with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended, relating to (i) shares of common stock of the Company, par value $0.01 per share (the “Common Stock”); (ii) shares of preferred stock of the Company, par value $1.00 per share (the “Preferred Stock”); (iii) debt securities (“Debt Securities”); (iv) warrants to purchase Common Stock, Preferred Stock or Debt Securities (the “Warrants”); (v) contracts for the purchase and sale of the Securities (as defined below) (the “Purchase Contracts”); (vi) units consisting of one or more of the Securities (the “Units”) and (vii) Common Stock, Preferred Stock or Debt Securities that may be issued upon conversion, exchange or exercise of Preferred Stock, Debt Securities, Warrants or Purchase Contracts, whichever is applicable. The Common Stock, the Preferred Stock, the Debt Securities, the Warrants, the Purchase Contracts and the Units are hereinafter referred to collectively as the “Securities.” The Securities may be issued and sold or delivered from time to time for an indeterminate aggregate initial offering price.

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The Debt Securities will be issued under the Indenture, dated as of September 17, 2018, between the Company and U.S. Bank National Association, as trustee (the “Indenture”).

The Warrants will be issued pursuant to one or more warrant agreements (each, a “Warrant Agreement”), between the Company and a warrant agent named therein.

The Purchase Contracts will be issued pursuant to one or more purchase contract agreements (each, a “Purchase Contract Agreement”), between the Company and a purchase contract agent named therein.

The Units will be issued pursuant to one or more unit agreements (each, a “Unit Agreement”), between the Company and a unit agent named therein (a “Unit Agent”).

The Indenture, the Warrant Agreements, the Purchase Contract Agreements and the Unit Agreements are hereinafter referred to collectively as the “Securities Agreements.”

We have examined the Registration Statement and the Indenture (including the form of Debt Securities set forth therein), which is an exhibit to the Registration Statement. In addition, we have examined, and have relied as to matters of fact upon, originals, or duplicates or certified or conformed copies, of such records, agreements, documents and other instruments and such certificates or comparable documents of public officials and of officers and representatives of the Company and have made such other investigations as we have deemed relevant and necessary in connection with the opinions hereinafter set forth.

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In rendering the opinions set forth below, we have assumed the genuineness of all signatures, the legal capacity of natural persons, the authenticity of all documents submitted to us as originals, the conformity to original documents of all documents submitted to us as duplicates or certified or conformed copies, and the authenticity of the originals of such latter documents. We also have assumed that, at the time of execution, authentication, issuance and delivery of any of the Securities, the applicable Securities Agreement will be the valid and legally binding obligation of each party thereto other than the Company.  We also have assumed that, with respect to the issuance of any shares of Common Stock or Preferred Stock, the amount of valid consideration paid in respect of such shares will equal or exceed the par value of such shares.

In rendering the opinions set forth below, we have assumed further that, at the time of execution, authentication, issuance and delivery, as applicable, of each of the applicable Securities Agreements (other than the Indenture) and Securities, (1) the Company will be validly existing and in good standing under the law of the jurisdiction in which it is organized and such Securities Agreement will have been duly authorized, executed and delivered by the Company in accordance with its organizational documents and the law of the jurisdiction in which it is organized, (2) the execution, delivery, issuance and performance, as applicable, by the Company of such Securities Agreement and such Securities will not constitute a breach or violation of its organizational documents or violate the law of the jurisdiction in which it is organized or any other jurisdiction (except that no such assumption is made with respect to the law of the State of New York or the Delaware General Corporation Law, assuming there shall not have been any change in such laws affecting the validity or enforceability of such Securities Agreement and such Securities) and (3) the execution, delivery, issuance and performance, as applicable, by the Company of such Securities Agreement and such Securities (a) will not constitute a breach or default under any agreement or instrument which is binding upon the Company and (b) will comply with all applicable regulatory requirements.

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In rendering the opinions set forth below, we have assumed further that the execution, issuance, delivery and performance by the Company of the Indenture (a) do not constitute a breach or default under any agreement or instrument which is binding upon the Company and (b) comply with all applicable regulatory requirements.

Based upon the foregoing, and subject to the qualifications, assumptions and limitations stated herein, we are of the opinion that:

1.          With respect to the Common Stock, assuming (a) the taking of all necessary corporate action to authorize and approve the issuance of the Common Stock and the terms of the offering thereof so as not to violate any applicable law or agreement or instrument then binding on the Company and (b) due issuance and delivery of the Common Stock, upon payment therefor in accordance with the applicable definitive underwriting, purchase or similar agreement approved by the Board of Directors of the Company and otherwise in accordance with the provisions of such agreement, the Company’s Amended and Restated Certificate of Incorporation and the Delaware General Corporation Law, the Common Stock will be validly issued, fully paid and nonassessable.

2.          With respect to the Preferred Stock, assuming (a) the taking of all necessary corporate action to authorize and approve the issuance and terms of the Preferred Stock and the terms of the offering thereof so as not to violate any applicable law or agreement or instrument then binding on the Company, (b) due filing of the applicable definitive Certificate of Designations with respect to such Preferred Stock and (c) due issuance and delivery of the Preferred Stock, upon payment therefor in accordance with the applicable definitive underwriting, purchase or similar agreement approved by the Board of Directors of the Company and otherwise in accordance with the provisions of such agreement, the Company’s Amended and Restated Certificate of Incorporation and the Delaware General Corporation Law the Preferred Stock will be validly issued, fully paid and nonassessable.

3.          With respect to the Debt Securities, assuming (a) the taking of all necessary corporate action by the Board of Directors of the Company or duly authorized officers of the Company (such Board of Directors or authorized officers being referred to herein as the “Company Authorizing Party”) to authorize and approve the issuance and terms of any Debt Securities and the terms of the offering thereof so as not to violate any applicable law or agreement or instrument then binding on the Company, and (b) the due execution, authentication, issuance and delivery of such Debt Securities, upon payment therefor in accordance with the applicable definitive underwriting, purchase or similar agreement approved by the Company Authorizing Party and otherwise in accordance with the provisions of such agreement and the Indenture, such Debt Securities will constitute valid and legally binding obligations of the Company enforceable against the Company in accordance with their terms.

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4.          With respect to the Warrants, assuming (a) the taking of all necessary corporate action by the Board of Directors of the Company to authorize and approve the issuance and terms of any Warrants and the terms of the offering thereof so as not to violate any applicable law or agreement or instrument then binding on the Company and (b) the due execution, countersignature, issuance and delivery of such Warrants, upon payment therefor in accordance with the applicable definitive underwriting, purchase or similar agreement approved by the Board of Directors of the Company and otherwise in accordance with the provisions of such agreement and the applicable definitive Warrant Agreement, such Warrants will constitute valid and legally binding obligations of the Company enforceable against the Company in accordance with their terms.

5.          With respect to the Purchase Contracts, assuming (a) the taking of all necessary corporate action by the Board of Directors of the Company to authorize and approve the issuance and terms of any Purchase Contracts and the terms of the offering thereof so as not to violate any applicable law or agreement or instrument then binding on the Company and (b) the due execution, issuance and delivery of such Purchase Contracts, upon payment therefor in accordance with the applicable definitive underwriting, purchase or similar agreement approved by the Board of Directors of the Company and otherwise in accordance with the provisions of such agreement and the applicable definitive Purchase Contract Agreement, such Purchase Contracts will constitute valid and legally binding obligations of the Company enforceable against the Company in accordance with their terms.

6.          With respect to the Units, assuming (a) the taking of all necessary corporate action by the Board of Directors of the Company to authorize and approve the issuance and delivery to the Unit Agent of the Securities that are the components of any Units, the issuance and terms of such Units and the terms of the offering thereof so as not to violate any applicable law or agreement or instrument then binding on the Company and (b) the due execution, authentication, issuance and delivery, as applicable, of such Units and the Securities that are the components of such Units, in each case upon payment therefor in accordance with the applicable definitive underwriting, purchase or similar agreement approved by the Board of Directors of the Company and otherwise in accordance with the provisions of such agreement and the applicable definitive Securities Agreements, the Company’s Amended and Restated Certificate of Incorporation and the Delaware General Corporation Law, such Units will constitute valid and legally binding obligations of the Company enforceable against the Company in accordance with their terms.

Our opinions set forth in paragraphs 3 through 6 above are subject to (i) the effects of bankruptcy, insolvency, fraudulent conveyance, reorganization, moratorium and other similar laws relating to or affecting creditors’ rights generally, (ii) general equitable principles (whether considered in a proceeding in equity or at law) and (iii) an implied covenant of good faith and fair dealing. In addition, we express no opinion as to the validity, legally binding effect or enforceability of Section 1.10 of the Indenture relating to the separability of provisions of the Indenture.

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We do not express any opinion herein concerning any law other than the law of the State of New York and the Delaware General Corporation Law.

We hereby consent to the filing of this opinion letter as Exhibit 5 to the Registration Statement and to the use of our name under the caption “Validity of Securities” in the Prospectus included in the Registration Statement.

Very truly yours,

/s/ Simpson Thacher & Bartlett LLP

SIMPSON THACHER & BARTLETT LLP