CTLA4 and neoplasm: Immunotherapeutic approaches like cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death-1/programmed cell death-ligand 1 (PD-1/PD-L1), chimeric antigen receptor (CAR) T cells, tumor antigens, vaccines, and targeted CSC therapies are promising treatments [12,13,14,15].