CTLA4 and neoplasm: ICIs, including PD-L1 or cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibodies, in combination with RT synergistically induced tumor ferroptosis, while blocking ferroptosis, pharmacologically or genetically, attenuated the therapeutic effectiveness afforded by combining ICIs with RT; conversely, the therapeutic synergy of immunotherapy and RT could be further enhanced by inactivating SLC7A11 in tumors (Lang et al., 2019).