It is known that the interaction between cancer and the immune system is a dynamic process [51]; the expression of PD-L1 can be regulated at the transcriptional, posttranscriptional, and protein levels [7], and the combination of other therapies may promote the activation of dendritic cells, the infiltration of T cells, and the exposure of neoantigens, which result in increases in PD-L1 expression and facilitate the efficacy of the PD-1/PD-L1 blockade. This evidence concerns the gene PDCD1 and cancer.