X0306 4 2020-12-10 0 0001750019 TCR2 THERAPEUTICS INC. TCRR 0001362054 Baeuerle Patrick TCR2 THERAPEUTICS INC. 100 BINNEY STREET CAMBRIDGE MA 02142 1 0 0 0 Common Stock 350786 I By APAK Solutions GmbH Stock Option (Right to Buy) 31.83 2020-12-10 4 A 0 12100 0.00 A 2030-12-09 Common Stock 12100 12100 D The reported securities are owned directly by APAK Solutions GmbH. The Reporting Person is managing director of APAK Solutions GmbH. The Reporting Person disclaims beneficial ownership of the securities reported herein except to the extent of his pecuniary interest therein. 25% of this option shall vest and become exercisable on January 1, 2022, with the remainder vesting in twenty-four (24) equal monthly installments thereafter. /s/ Margaret Siegel as Attorney-in-Fact 2020-12-10