Inclusion Criteria:  ECOG Performance Status of 0 or 1 Histologically confirmed, metastatic (recurrent or de novo Stage IV) or unresectable locally advanced (Stage III) cutaneous melanoma, that has progressed on or after treatment with anti-PD-1 or anti-PD-L1 therapy. Patients may have received up to two lines of systemic cancer therapy. Treatment with anti-PD-1/PD-L1 in the adjuvant setting is acceptable. Patients must have progressive disease at study entry Documentation of NRAS mutation-positive within 5 years prior to screening Tumor specimen availability Adequate hematologic and end-organ function Measurable disease per RECIST v1.1  Exclusion Criteria:  Treatment with systemic immunotherapy agents (e.g., anti-CTLA4, anti-PD(L)1, cytokine therapy, investigational therapy, etc.) within 28 days prior to C1D1 Symptomatic, untreated, or actively progressing CNS metastases History or signs/symptoms of clinically significant cardiovascular disease Known clinically significant liver disease History of autoimmune disease or immune deficiency Prior treatment with a MEK inhibitor (cobimetinib arm) History of or evidence of retinal pathology on ophthalmologic examination (cobimetinib arm) History of immune-related AE attributed to prior anti-PD(L)1 therapy that resulted in permanent discontinuation of anti-PD(L)1 therapy (atezolizumab arm)