X0206 3 2018-03-28 0 0001622229 Unum Therapeutics, Inc. UMRX 0001451612 Booth Bruce C/O UNUM THERAPEUTICS INC. 200 CAMBRIDGE PARK DRIVE, SUITE 3100 CAMBRIDGE MA 02140 1 0 0 0 Series A Preferred Stock Common Stock 3184446 I See footnote Series B Preferred Stock Common Stock 83037 I See footnote Each share is convertible on a 1.5701314513884-for-1 basis into Common Stock at any time at the election of the Reporting Person and will automatically convert upon the closing of the Issuer's initial public offering into the number of shares of the Issuer's Common Stock shown in column 3 without payment or further consideration. The shares have no expiration date. The shares are held directly by Atlas Venture Fund IX, L.P. ("Atlas Venture Fund IX"). The general partner of Atlas Venture Fund IX is Atlas Venture Associates IX, L.P. ("AVA IX LP"). Atlas Venture Associates IX, LLC ("AVA IX LLC") is the general partner of AVA IX LP. Dr. Booth is a member of AVA IX LLC and disclaims beneficial ownership of such securities held by Atlas Venture Fund IX, except to the extent of his pecuniary interest therein, if any. Exhibit 24 - Power of Attorney (filed herewith) /s/ Bruce Booth 2018-03-28