The agents currently in use can target either Programmed Death-1 Receptor (PD-1) and Cytotoxic T Lymphocyte Associated Protein-4 (CTLA-4) located on T cells, or Programmed Death Ligand-1 (PD-L1) located on tumor cells, thus counteracting the main mechanisms by which tumor cells exploit the immune response and generate immune tolerance towards tumor cells. The gene discussed is CTLA4; the disease is neoplasm.