Programmed death-1 (PD-1), which is expressed on the surface of immune cells, and its ligand programmed cell death-1 ligand 1 (PD-L1), which is expressed in various tumor tissues, are significant immunosuppressive molecules, and their interaction can induce T cell apoptosis and inhibit T cell proliferation, promoting tumor progression. The gene discussed is CD274; the disease is neoplasm.