9. Pregnancy Test or FSH Level (Serum): For female participants of childbearing potential, a serum or urine pregnancy test, with sensitivity of a t least 25 mIU/mL and assayed in a certified laboratory, will be performed on 2 occasions prior to starting study therapy, once at the start of screening and once at the baseline visit immediately before investigational product administration. Pregnancy tests will also be routinely repeated at Day 1 of every treatment cycle during the active treatment period, at the End of Treatment visit, at the 28-day Follow-Up Visit, and additionally whenever one menstrual cycle is missed or when potential pregna ncy is otherwise suspected. Additional CCI PF-06936308 C3621001Final Protocol Amendment 2, 22 Dec 2020 PFIZER CONFIDENTIAL Page 24Protocol Activity Maintenance Treatment Period* Study Month ** Month 9 Month 10Month 11Month 12Month 13Month 14Month 15Month 16Month 17Month 18 Month 19Month 20Month 21Month 22 and every month thereafte r Visit Window (Days) ±7 ±7 ±7 ±7 ±7 ±7 ±7 ±7 ±7 ±7 ±7 ±7 ±7 ±7 pregnancy tests may also be undertaken if requested by institutional review board/ethics committee (IRB/ECs) or if required by local regulations. Participants with confrmed positive pregnanct test(s) should not be dosed. For female participants who achieved postmenopausal status and have not experi enced their menses for at least 12 consecutive months, a serum FSH test must be conducted at screening only to confirm a FSH level within the laboratory’s reference ranges. 10. Contraception Check: Male participants who are able to father children and female participants who are of childbearing potential will need to affirm that they meet the criteria for correct use of 2 of the selected methods of contraception. The investigator or his or her designee will discuss wi th the participant the need to use 2 highly effective contraception methods consistently and correctly and document such conversation in the participant’s chart. In addition, the in vestigator or his or her designee will instruct the participant to call immediately if one or both selected contraception methods are discontinued, or if pregnancy is known or suspected in the participant or the participant’s partner. 11. To be assessed every 4 months. 12. Triplicate 12 leads ECGs: At each time point, three consecutive 12 lead ECGs will be performed approximately 2 minutes apart to determine mean QTcF inter val. If the mean QTcF is prolonged (>500 msec), the ECGs should be reevaluated by a qualified person at the institution for confirmation. Additional triplicate ECGs will be performed at Month 12 Day 1, Month 18 Day 1, or may be performed as clinically indicated. 13. Investigational Product Administration: Treatment to be administered after all other assessments required on that day have been performed, including pregnancy test. Al l participants will continue to receive the components to which they were assigned to receive during the treatment period. – note e ither the tremelimumab or the sasanlimab may be dose reduced or permanently discontinued after discussion with the Sponsor for participants assigned to receive these co mponents. 14.