PDCD1 and nasopharyngeal carcinoma: Consistent with these findings, transcriptomic studies reported that CD4+ and CD8+ T-cells clusters in NPC are highly activated and exhausted, as they co-express exhaustion markers (LAG3, TIGIT, PDCD1, HAVCR2, CTLA4, TOX) and effector molecules (GZMB, GZMK, INFG, NKG7, GNLY, and IL2) (17–21).