CTLA4 and metastatic neoplasm: Meanwhile, the metastatic tumors are abolished effectively with the support of oligodeoxynucleotides containing cytosine–guanine together with systemic checkpoint blockade immunotherapy using an anti-CTLA4 (anti-cytotoxic T lymphocyte associated antigen-4) antibody [145], providing a multifunctional platform for anticancer therapeutic applications through ferroptosis.