The high expression in neoplastic cells from several cancer types of its ligands, programmed death-ligands 1 and 2 (PD-L1 and PD-L2), surface molecules involved in the suppression of T cell responses in vivo [145] have drawn, on the PD-1/PD-L1 axis, the attention of the scientific and pharmaceutical community [9,146]. This evidence concerns the gene CD274 and cancer.