CCL21 and nasopharyngeal carcinoma: Based on the single‐cell sequencing derived from NPC clinical samples, RANBP17 is expressed in EBV‐associated NPC cells, KCNJ10 is detectable in myeloid cells, and CXCR5 is dormantly expressed by B cells, while cancer‐associated fibroblasts mainly express CCL19 and CCL21 (Table S5 and Figures S6 and S7).