By competing with the co-stimulatory molecule CD226 for binding to the ligand CD155, TIGIT inhibits the CD226-mediated T cell activation signal, thereby weakening T cell cytokine secretion and proliferation capacity (66, 67), in addition to its combination with PD-1 inhibitors in anti-tumor therapy, recent studies have found that combined blockade of CD47 and TIGIT targets can enhance the phagocytic activity of macrophages against leukemia in vitro. The gene discussed is PDCD1; the disease is neoplasm.