Tumor cells are able to evade the immune system by modulating immune checkpoint pathways, as well as by increasing programmed death-ligand 1 (PD-L1), making tumor-infiltrated lymphocytes (TILs) that express the programmed cell death protein 1 (PD-1) receptor ineffective despite being present in the tumor microenvironment [7,8]. Here, PDCD1 is linked to neoplasm.