This is a non-interventional, observational study with the primary objective to assess and describe "real world" patterns of care in the treatment of patients with unresectable or metastatic melanoma. A sample size of 1,600 prospective patients will provide sufficient information to explore this primary objective. There will be no forced number of patients enrolled into a specific treatment cohort. Setting or controlling specific treatment enrollment cohort counts would invalidate the results of the primary objective of the study. No primary hypothesis is being tested.