These monoclonal antibodies work by disrupting the immunosuppressive signals generated by cancer cells through targeted blockade of cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and programmed death protein 1 (PD-1) on T cells, or its ligand on tumour cells, programmed death ligand 1 (PD-L1). The gene discussed is CTLA4; the disease is cancer.