PDCD1 and metastatic melanoma: The clinical benefit of immunotherapy was supported by convincing evidence in the following settings: anti-PD-1/PD-L1 monoclonal antibody (mAb) therapy for treating advanced melanoma and non-small cell lung cancer (NSCLC), the combination of rituximab and chemotherapy for treating chronic lymphocytic leukemia and B-cell non-Hodgkin’s lymphoma, adoptive cell immunotherapy for NSCLC, and the combination of interferon α and chemotherapy for metastatic melanoma.