A Phase II Study of Sacituzumab Govitecan With or Without Atezolizumab Immunotherapy in Rare Genitourinary Tumors (SMART) Such as High Grade Neuroendocrine Carcinomas, Adenocarcinoma, and Squamous Cell Bladder/Urinary Tract Cancer, Renal Medullary Carcinoma and Penile Cancer | Arctuva