In the past decades, pre-clinical experiments and clinical trials showed significant efficacy of immune checkpoint blockade in various cancers (19–21), indeed, several immune checkpoint inhibitors including anti-PD-1 have now been approved by the FDA for the treatment of melanoma, non-small-cell lung carcinoma, kidney carcinoma, gastric cancer, etc. The programmed cell death pathway is one of the most characterized immune evasion mechanisms (22). This evidence concerns the gene PDCD1 and cancer.