CD80 and neoplasm: Immunotherapy using antibodies that block interactions between inhibitory immune checkpoint receptors on T cells and their ligands on tumor cells and/or immune cells, such as binding of CTLA-4 to B7-1 and/or B7-2, and binding of PD1 to PD-L1, thereby unleashing inhibition of anti-tumor T-cells, has shown considerable clinical benefits in several types of solid cancers (13).