Another immunosuppressive mechanism allowing immune evasion is given by the interaction between programmed death-1 (PD-1) expressed on T-cells, activated B cells, activated NK cells and TILs in different tumor types, and PD-L1 and PD-L2 (PD-L1/2), which are expressed on tumor cells and other cells in the tumor microenvironment [6]. This evidence concerns the gene PDCD1LG2 and neoplasm.