X0306 4 2020-11-17 0 0001640455 Jounce Therapeutics, Inc. JNCE 0001591092 Pfeffer Cary C/O THIRD ROCK VENTURES, LLC, 29 NEWBURY STREET, 3RD FLOOR BOSTON MA 02116 1 0 0 0 Common Stock 2020-11-17 4 S 0 0 0.00 D 0 I See Footnote Common Stock 9917 D On November 17, 2020, Third Rock Ventures II, L.P. ("TRV II") sold 15,000 shares of Common Stock of the Issuer at a price per share of $7.2515. After the above transaction, TRV II owned 9,215,349 shares of Common Stock of the Issuer. The Reporting Person is a partner of Third Rock Ventures GP II, L.P., which is the general partner of TRV II. The Reporting Person disclaims beneficial ownership over the shares held by TRV II, except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that he is the beneficial owner of such shares. Third Rock Ventures III, L.P. ("TRV III") directly holds 3,048,780 shares of the Issuer's Common Stock. The Reporting Person is a partner of Third Rock Ventures GP III, L.P., which is the general partner of TRV III. The Reporting Person disclaims beneficial ownership over the shares held by TRV III, except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that he is the beneficial owner of such shares. Exhibit 24 - Power of Attorney /s/ Kevin Gillis, by power of attorney 2020-11-19