CTLA4 and nasopharyngeal carcinoma: In addition to T‐cell sufficiency, we observed elevated immune tolerance in the NPC group, which was associated with an increase in the number of PD‐1+ T cells, CTLA4+ T cells, MHC II+ T cells and Treg cells in the NPC group (Figure 3), thus potentially diminishing the clinical benefits of tumour‐specific cytotoxic T cells.35