For instance, PD-L1 is mischaracterized as a ligand for PD-1 while it is a bi-directional receptor originally known as B7-H1, which upon engagement with PD-1, transmits survival signals via anti-apoptotic pathways, such as Bcl-xL induction in the target cells or tumor [74–78] (Fig. 1A). This evidence concerns the gene CD274 and neoplasm.