X0306 4 2021-05-28 0 0001651431 Checkmate Pharmaceuticals, Inc. CMPI 0001335659 Krieg Arthur M C/O CHECKMATE PHARMACEUTICALS, INC. 245 MAIN STREET, 2ND FLOOR CAMBRIDGE MA 02142 0 1 0 0 Chief Scientific Officer Common Stock 2021-05-28 4 J 0 68457 0.00 D 0 I See footnote Common Stock 2021-05-28 4 J 0 68457 0.00 D 0 I See footnote Common Stock 2021-05-28 4 J 0 68457 0.00 D 0 I See footnote Common Stock 804932 D The shares were held by an irrevocable trust for the Reporting Person's child. The Reporting Person serves as trustee of the trust, which is being dissolved at the discretion of the trustee . On May 28, 2021, share ownership of the 68,457 shares of common stock which were held in the trust, for which the Reporting Person had previously disclaimed beneficial ownership of, were transferred to the Reporting Person's adult child, the beneficiary of the trust, who does not live in the same household as the Reporting Person. Exhibit 24 - Power of Attorney /s/ Katherine Eade, attorney-in-fact 2021-06-01