Since first ICB targeting cytotoxic T lymphocyte antigen 4 (CTLA-4), ipilimumab, garnered approval for the treatment of melanoma in 2011 (Hodi et al., 2010; Robert et al., 2011), ICBs targeting programmed cell death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) are also being investigated in the clinical trials, manifesting compelling clinical effectiveness (Ansell et al., 2015; Borghaei et al., 2015; Larkin et al., 2015). This evidence concerns the gene PDCD1 and melanoma.