PD1-PD-L1 inhibitor 1 (PD1-PD-L1-IN-1) is an inhibitor of the PD1-PD-L1 protein-protein interaction. It also acts as an immunomodulator. Programmed death ligand 1 (PD-L1) is a protein in humans that is encoded by the CD274 gene and the upregulation of PD-L1 allows Ys to evade the host immune system. High tumor expression of PD-L1 was associated with increased tumor aggressiveness and a 4.5-fold increased risk of death.