PDCD1 and melanoma: Immune checkpoints that have been extensively studied in melanoma to date include PD-1/programmed cell death ligand-1 (PD-L1) and CTLA-4.18 To enhance the benefit from ICI in melanoma, there has recently been an evolving focus on identifying and targeting alternative novel immune checkpoints.17 LAG-3, which is a co-inhibitory receptor that suppresses T-cell activation and cytokine secretion, can be a promising immune checkpoint.17,18