STAT3 and cancer: Importantly, coexpression of IRF1 and STAT3 in ATXN3-KO cancer cells fully rescued IFN-γ–induced PD-L1 expression, but had little effect on hypoxia-induced PD-L1 expression, confirming that ATXN3 promotes IFN-γ–induced PD-L1 expression specifically through stabilizing IRF1 and STAT3.