PDCD1 and metastatic melanoma: Immunotherapy (IO), including anti-programmed cell death protein 1 (anti-PD1) and anti-cytotoxic T lymphocyte-associated protein 4 (anti-CTLA-4) therapies (5), and targeted therapy (TT) against BRAF V600 E/K mutations (BRAFi) and MEK/MAPK signaling pathways (MEKi) (6), have improved progression-free survival (PFS) and overall survival (OS) of patients with metastatic melanoma and reached median OS of up to 24.3 months (7).