CD274 and cancer: The first generation of BiTEs targeted antigens associated with the surface of tumor cells, thereby recognizing the same cell population as the OV.7 13 14 Subsequent generations targeted antigens expressed on stromal cells such as tumor-associated fibroblasts, providing a strategy whereby the OV and activated T cells are cytotoxic to different cell populations within the tumor.9 12 Here we have taken this concept further and designed an OV encoding a BiTE targeting the pan-cancer antigen, programmed death-ligand 1 (PD-L1).