Programmed death-ligand 1 (PD-L1) is a 40 kDa type 1 transmembrane protein that suppresses immune system. PD-L1 is expressed in hematopoietic and non-hematopoietic cells including T cells and B cells and various types of tumor cells. PD-L1 binds to its receptor Programmed death 1 (PD1). During infection or inflammation, PD1-PD-L1 interaction is important for preventing autoimmunity. In tumor microenvironments, PD1-PD-L1 interaction provides an immune escape for tumor cells through cytotoxic T-cell inactivation. Expression of this gene in tumor cells is considered to be prognostic in many types of human cancers. In recent years, PD-L1 has become an important biomarker and immunotherapy target for many types of malignancies.,B7-H,B7H1,PDL1,PD-L1,PDCD1L1,PDCD1LG1,CD274,Immunology & Inflammation,CD markers,PD-L1