Due to remarkable survival benefits of cancer immunotherapy, FDA approved the treatment of several cancer entities by using antibodies blocking the negative immune checkpoint molecules, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1) or PD-1 ligand 1 (PD-L1) [5]. This evidence concerns the gene PDCD1 and cancer.