The PD-L1 protein critically regulates immune tolerance by acting as a ligand for PDCD1/PD-1, regulating T cell activation threshold, and limiting effector responses. It may act as a costimulatory molecule for IL10-producing T cell subsets. PD-L1 Protein, Cynomolgus/Rhesus Macaque (Biotinylated, HEK293, His) is the recombinant Rhesus Macaque-derived PD-L1 protein, expressed by HEK293 , with C-His labeled tag.