Giuseppina Improta,1 Isabella Leone,1 Marco Donia,2 Stefania Gieri,3 Giuseppe Pelosi,4,5 Filippo Fraggetta6 1Laboratory of Clinical Research and Advanced Diagnostics, IRCCS-CROB, Rionero in Vulture, Potenza, Italy; 2Center for Cancer Immune Therapy, Department of Hematology, Copenhagen University Hospital, Herlev, Denmark; 3Laboratory of Oncologic Technologies, IBFM-CNR, Cefalù, Potenza, 4Department of Pathology and Laboratory Medicine, Fondazione IRCCS Istituto Nazionale Tumori, Milan, 5Department of Biomedical and Clinical Sciences “Luigi Sacco”, Università degli Studi di Milano, Milan, 6Department of Pathology, Cannizzaro Hospital, Catania, Italy Abstract: Cancer immunotherapy is now recognized to be fundamental in modern oncology, because immune system recruitment may represent a powerful and innovative strategy in cancer therapy. Pembrolizumab, a highly selective humanized monoclonal antibody directly blocking the interaction between programmed cell death-1 expressed by tumor-associated T-cells and its ligand programmed cell death-L1 present on tumor and stromal cells, was recently approved by US Food and Drug Administration for the treatment of patients with unresectable or metastatic melanoma and disease progression upon ipilimumab and BRAF inhibitor. This review will focus on the clinical development and use of pembrolizumab in the clinical practice and in the management of advanced melanoma. Keywords: advanced melanoma, immunotherapy, PD-1 inhibitor, pembrolizumab