X0306 4 2020-08-11 0001651431 Checkmate Pharmaceuticals, Inc. CMPI 0001634632 venBio Global Strategic Fund II L.P. 1700 OWENS STREET SUITE 595 SAN FRANCISCO CA 94158 true 0001729409 venBio Global Strategic GP II, L.P. 1700 OWENS STREET SUITE 595 SAN FRANCISCO CA 94158 true 0001729408 venBio Global Strategic GP II, Ltd. 1700 OWENS STREET SUITE 595 SAN FRANCISCO CA 94158 true 0001278411 GOODMAN COREY S 1700 OWENS STREET SUITE 595 SAN FRANCISCO CA 94158 true 0001329161 Adelman Robert J 1700 OWENS STREET SUITE 595 SAN FRANCISCO CA 94158 true Common Stock 2020-08-11 4 C 0 3473374 A 3473374 D Common Stock 2020-08-11 4 P 0 200000 15 A 3673374 D Series A Preferred Stock 2020-08-11 4 C 0 12500000 0 D Common Stock 1671771 0 D Series B Preferred Stock 2020-08-11 4 C 0 8753350 0 D Common Stock 1314165 0 D Series C Preferred Stock 2020-08-11 4 C 0 3644624 0 D Common Stock 487438 0 D The Series A Preferred Stock and Series C Preferred Stock automatically converted into Common Stock at a rate of 1:7.4771 upon the closing of the Issuer's initial public offering without payment of consideration. The Series A Preferred Stock and Series C Preferred Stock were convertible at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. The shares had no expiration date. The Series B Preferred Stock automatically converted into Common Stock at a rate of 1.12256:7.4771 upon the closing of the Issuer's initial public offering without payment of consideration. The Series B Preferred Stock was convertible at any time at the holder's election and automatically upon the closing of the Issuer's initial public offering. The shares had no expiration date. The shares are held by venBio Global Strategic Fund II, L.P. venBio Global Strategic GP II, L.P. is the sole general partner of venBio Global Strategic Fund II, L.P. and venBio Global Strategic GP II, Ltd. is the sole general partner of venBio Global Strategic GP II, L.P. Each of Corey Goodman and Robert Adelman is a director of venBio Global Strategic GP II, Ltd. Each of venBio Global Strategic GP II, L.P., venBio Global Strategic GP II, Ltd., Dr. Goodman and Dr. Adelman disclaims beneficial ownership of such securities, except to the extent of its/his indirect pecuniary interest therein. venBio Global Strategic Fund II, L.P., by: venBio Global Strategic GP II, L.P., its general partner, by: venBio Global Strategic GP II, Ltd., its general partner, by: /s/ David Pezeshki, as attorney-in-fact 2020-08-12 venBio Global Strategic GP II, L.P., by: venBio Global Strategic GP II, Ltd., its general partner, by: /s/ David Pezeshki as attorney-in-fact 2020-08-12 venBio Global Strategic GP II, Ltd., by: /s/ David Pezeshki, as attorney-in-fact 2020-08-12 Corey Goodman, by: /s/ David Pezeshki, as attorney-in-fact 2020-08-12 Robert Adelman, by: /s/ David Pezeshki, as attorney-in-fact 2020-08-12