These include immune checkpoint inhibitors (CTLA4 and PD-1/PD-L1 axis) (1–4), specific monoclonal antibodies (5), immunostimulants (e.g., BCG) (6), cancer vaccines (7), and the adoptive transfer of tumor-reactive immune cells, known as adoptive cell therapy (ACT) (8). The gene discussed is PDCD1; the disease is neoplasm.