This is an open-label, non-controlled, non-randomized, phase I dose-finding, of Cabometyx + Avelumab, to establish safety, feasibility, and the maximum tolerated dose (MTD) or Recommended Phase 2 Dose (RP2D) of Cabometyx in combination with Avelumab, and to investigate preliminary efficacy. The MTD or RP2D determined in this study will be used for a future study to formally test efficacy.