Some tumor cells exhibit the ability to misuse the immune checkpoint pathways to protect themselves from immune surveillance by blocking the T cells activity through immune checkpoint ligands expressed on the tumor cell surface including programmed cell death ligand 1 (PD-L1), programmed cell death ligand 2 (PD-L2), B7-1, B7-2, liver and lymph node sinusoidal endothelial cell C-type lectin (LSECtin/CLEC4G), Fibrinogen-like protein 1 (FGL1), Galectin-3, HMGB1, PtdSer, Cecam2, Galectin-9, CD112/CD155, and some other not fully characterized. This evidence concerns the gene PDCD1LG2 and neoplasm.