The previously reported FGL1–LAG-3 interaction51 was not obvious in NPC, primarily due to the low expression of FGL1 in the tumor cells (Supplementary information, Fig. S11b); MHC-II was predominantly responsible for the inhibitory function of LAG-3 induced by the interaction between dysfunctional T cells and tumor cells. Here, LAG3 is linked to nasopharyngeal carcinoma.