Blocking CD28 with antibodies on human T cells or using T cells from PD1−/− and CD28−/− mice showed that sB7-1-mediated anti-cancer immunity was not only dependent on neutralizing PD-1/PD-L1-mediated immune suppression but also a simultaneous B7-1-CD28 co-stimulation (103–105). Here, CD80 is linked to cancer.