Atezolizumab in Combination With Bevacizumab in Patients With Unresectable Locally Advanced or Metastatic Mucosal Melanoma

Inclusion Criteria: * Histologically confirmed unresectable locally advanced(stage III) or metastatic(Stage IV) mucosal melanoma * May have received prior systemic treatment or treatment naive at enrollment * Measurable disease per RECIST v1.1 * ECOG Performance Status of 0-1 * Life expectancy \>= 12 weeks * Adequate hematologic and end-organ function * Negative HIV test at screening * Negative hepatitis B surface antigen test at screening * Negative hepatitis B core antibody at screening, or positive total HBcAb test followed by quantitative hepatitis B virus DNA\<500 IU/mL at screening. * Negative hepatitis C virus (HCV) antibody test at screening, or positive HCV antibody test followed by a negative HCV RNA test at screening * For women of childbearing potential: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive methods, and agreement to refrain from donating eggs * For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraceptive measures, and agreement to refrain from donating sperm Exclusion Criteria: * Symptomatic or actively progressing central nervous system (CNS) metastases * History of leptomeningeal disease * Uncontrolled tumor-related pain * Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures * Uncontrolled or symptomatic hypercalcemia * Active or history of autoimmune disease or immune deficiency, including, but not limited to, myasth…