CTLA4 and neoplasm: ICIs block crucial immune checkpoint proteins hijacked by tumors, such as Cytotoxic T Lymphocyte Associated Protein 4 (CTLA-4), Programmed Cell Death Protein 1 (PD-1), and Programmed Cell Death Ligand 1 (PD-L1), therefore reversing tumor immune escape and enhancing the body’s immune response to tumors (Ke-Yu et al., 2024).