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)