ICOS and head and neck squamous cell carcinoma: The decreased B memory, CD8+ T, and Treg populations, together with the increased NK resting and M0 macrophage cell populations, were common in node-positive HNSCC with lower ICOS, or those cases with higher ratios of PD-L1, PD-L2, and CD276 relative to ICOS (Figure 7A,B).