Physical examinations, vital sign measurements, 12- lead electrocardiogram (ECG), and clinical laboratory evaluations will be pe rformed at selected times throughout the dosing interval. Participants will be closely monitored for AEs throughout the study. Blood will be collected at 30, 60, and 100-day follow-up visits ( Section 9.5 ) after study treatment ad ministration for PK analysis. Participants will complete up to 4 phases of the st udy: screening, treatment, safety follow-up, and response/survival follow-up, as described below. Total duration of participation in the study is approxi mately 4 years. The study design schematic is presented in Figure 5-1 . 5.1.1 Screening The screening phase will last for up to 28 days and take place prior to the first administration of study treatment. During the screening phase, the participant’s initial eligibility will be established, and written informed consent will be obtained. Tumor biopsies will be collected for all participants and sent for central evaluation of ICOS expression by immunohistochemistry, and all participants will receive the tetanus booster vaccine 3-7 days pri or to Cycle 1 Day 1 of first administration of study treatment. Stool w ill be coll ected for microbiota composition analysis.