The goal of this study is to describe patient characteristics, treatment outcomes and adverse events for patients with metastatic melanoma testing positive for PD-L1 expression treated first line (1L) with either nivolumab and ipilimumab in combination (NIVO + IPI) or nivolumab (NIVO) monotherapy

Inclusion Criteria:

• Adults 18 years or older
• First advanced of diagnosis of metastatic/Stage IV) melanoma
• Tested for PD-L1 expression with a tumor proportion score (TPS) greater than or equal to 1% (Phase 1 data collection)
• Initiating a first line of therapy during the index period between October 1, 2015 through July 1, 2017
• Medical history available for medical chart abstraction from date of diagnosis through most recent or current therapy (defined as end of data collection period)

Exclusion Criteria:

• Patients enrolled in a cancer treatment-related clinical trial prior to first line therapy initiation for metastatic/Stage IV) melanoma

Other protocol defined inclusion/exclusion criteria could apply

Adult metastatic melanoma patients with a positive PD-L1 expression level (above 1%) treated with nivolumab or nivolumab+ipilimumab in the first line setting in the US between Oct 1, 2015 and July 1, 2017