If you are in Part A (Phase 1B), you will be assigned a dose level of avelumab. Up to 4 dose levels of avelumab will be tested. Up to 18 participants will be enrolled at each dose level. If intolerable side effects are seen in the participants who received the highest dose level, the next group of participants will receive a lower dose than the group before it. This will continue until the highest tolerable dose of avelumab is found.