PDCD1 and melanoma: New melanoma adjuvant treatments include immunotherapy with programmed cell death protein 1 (PD-1), programmed death ligand-1 (PD-L1), or cytotoxic T-lymphocyte associated protein 4 (CTLA4) inhibitors or targeted drug therapies with BRAF, MAPK/ERK kinase 1 (MEK), or stem cell factor receptor (c-KIT) inhibitors [6,7,8].