PDCD1 and melanoma: The combination of B-Raf Proto-Oncogene (BRAF)- and Mitogen-Activated Protein Kinase Kinase 1 (MEK)-inhibitors has shown an important improvement in the prognosis of BRAF-V600E mutant MM cases, while immunotherapy with check-point inhibitors, like Programmed Cell Death 1 (PD-1) and/or Cytotoxic T-Lymphocyte Associated Protein 4 (CLTA-4) blocking antibodies, has shown activity in melanoma patients irrespective of their mutational status and is currently the recommended first-line therapy [15].