We treated SIRT7-overexpressed melanoma cell with IRE1α inhibitor STF083010 or the transfection with siRNA against XBP1, which displayed that the up-regulation of PD-L1 by SIRT7 was significantly suppressed at both mRNA and protein levels under ER stress (Fig. 6n, o; Supplementary Fig. S9b). This evidence concerns the gene XBP1 and melanoma.