X0206 3 2020-08-06 0 0001651431 Checkmate Pharmaceuticals, Inc. CMPI 0001335659 Krieg Arthur M C/O CHECKMATE PHARMACEUTICALS, INC. 245 MAIN STREET, 2ND FLOOR CAMBRIDGE MA 02142 1 1 0 0 Chief Scientific Officer Common Stock 720597 D Common Stock 68457 I See footnote Common Stock 68457 I See footnote Common Stock 68457 I See footnote The shares are held by an irrevocable trust for the Reporting Person's child. The Reporting Person serves as trustee of the trust. The Reporting Person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of all of the reported shares for purposes of Section 16 or for any other purpose. Exhibit 24 - Power of Attorney /s/ Kleem Chaudhary, attorney-in-fact 2020-08-06