PDCD1 and cancer: Programmed cell-death ligand 1 (PD-L1, B7-H1 or CD274), the complimentary ligand of Programmed cell-death 1 (PD-1), is expressed on the surface of cancer cells and recruited immune cells and suppresses the local immunological response to cancer cells by inducing apoptosis of tumour infiltrating lymphocytes (TILs), leading to propagation of tumour proliferation.