Since the first ICI (ipilimumab) was approved for advanced melanoma treatment by FDA in 2011, many drugs have gone through phase 3 trial and been applied in clinical fields, including anti-PD-1 monoclonal antibodies (nivolumab, pembrolizumab)/anti-PD-L1 monoclonal antibody (atezolizumab) and anti-CTLA-4 monoclonal antibody (ipilimumab) [50–52]. This evidence concerns the gene PDCD1 and melanoma.