Subsequent rescue experiments demonstrated that stable IDO1 overexpression in FLI1-KO NPC cells mitigated the suppression of Kyn production and AHR activity imposed by FLI1 KO, subsequently aggravating CD8+ T cell exhaustion (Supplementary Fig. S2D–F and Fig. 2G–J). Here, FLI1 is linked to nasopharyngeal carcinoma.