PDCD1LG2 and neoplasm: Pembrolizumab (Keytruda) is an immunotherapy agent that directly inhibits theprogrammed cell death 1 protein (PD-1), which prevents its interaction with programdeath ligand 1/program death ligand 2 (PDL1/PDL2).1,2 By preventing the interaction,T-cells are activated and causes apoptosis of the tumor cells that have PDL1 andPDL2.