X0206 3 2017-01-26 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 0 I See Footnote Series A Preferred Stock Common Stock 0 I See Footnote Series A Preferred Stock Common Stock 0 I See Footnote Third Rock Ventures II, L.P. ("TRV II") directly holds 542,005 shares of common stock and 9,688,344 shares of common stock issuable upon the conversion of shares of Series A Preferred Stock. Each share of Series A Preferred Stock is convertible, at any time, at the holder's election, into Common Stock of the Issuer on a one-for-3.69 basis. In addition, effective upon the closing of the Issuer's initial public offering of its Common Stock, each share of preferred stock will automatically convert on a one-for-3.69 basis without payment or consideration. The preferred stock has no expiration date. Third Rock Ventures III, L.P. ("TRV III") directly holds 3,048,780 shares of common stock issuable upon the conversion of Series A Preferred Stock. The reporting person is a partner of Third Rock Ventures GP III, L.P., which is the general partner of the TRV III. The reporting person disclaims beneficial ownership over such shares, 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/ Cary Pfeffer 2017-01-26