CXCR4 and head and neck squamous cell carcinoma: In the combined bulk cohort, the high IMS group also exhibited high expression of CD74 and CXCR4 (Figure 5H; p = 8.69e-151, p = 2.47e-67); therefore, these ligand–receptor pairs specifically enriched in HNSCC immune cell types may provide a clue for targeted immunotherapy.