ICI therapy is based on two major mechanisms through which tumor immune evasion capabilities are suppressed and anti-tumor activity by CD8+ T-cells is potentiated: inhibition of cytotoxic T-lymphocyte associated protein 4 (CTLA4) and inhibition of the programmed death 1 (PD-1) or PD ligand 1 (PD-L1) axis (Figure 2). This evidence concerns the gene CTLA4 and neoplasm.