CD8A and cancer: Notably, it has recently been demonstrated that restored immunotherapy-activated CD8+ cytotoxic T cells downregulate the expression of the system Xc- on tumor cells through IFNγ leading to enhanced lipid peroxidation and ferroptosis of tumor cells (Wang et al., 2019), suggesting a potential combinatorial therapeutic approach of removing checkpoints as well as targeting iron metabolism, for more effective cancer immunotherapy.