An observational study of melanoma participants who are eligible for and who have initiated treatment with adjuvant nivolumab as part of routine clinical practice.

Participants receiving adjuvant nivolumab therapy could be enrolled prospectively and retrospectively.

Inclusion Criteria:

• Patients with a primary diagnosis of melanoma with involvement of lymph nodes or metastatic disease who have undergone complete resection and have no evidence of disease.
• Decision to treat with adjuvant nivolumab therapy has already been taken
• At least 18 years of age at the time of treatment decision
• Patients who provide written informed consent to participate in the study (for retrospectively enrolled patients who are deceased at time of study start, a consent waiver will be sought)

Exclusion Criteria:

• Any patient with a diagnosis of persisting advanced melanoma prior to first administration of nivolumab
• Any patient currently enrolled in an interventional clinical trial for his/her melanoma treatment (note: patients who have completed their participation in an interventional trial or who are no longer receiving the study drug and are only followed up for Overall Survival (OS)/ Relapse Free Survival (RFS) can be enrolled. In case of a blinded study, the treatment arm needs to be known).

Other protocol defined inclusion/exclusion criteria could apply

Adults with melanoma with involvement of lymph nodes or metastatic disease who have undergone complete resection, and who receive adjuvant nivolumab under real-world conditions in Belgium or Luxembourg. Patients will be enrolled after complete surgical resection and following a screen procedure (according to standard practice) that shows no evidence of disease. Patients currently enrolled in an interventional clinical trial will not be eligible.