Figure 4B summarizes the results obtained from 502 HNSCC patients in the TCGA. In detail, patients with ICD-high subtype exhibited considerably elevated percentages of B cell plasma, CD8 T cell, resting CD4 T cell memory, activated CD4 T cell memory, T cell regulatory, macrophage M1 and M2, activated myeloid dendritic cell, and eosinophil cell (Figure 4C). Besides, most of the human leukocyte antigen (HLA) genes and immune checkpoints were upregulated in the ICD-high subtype. On the contrary, the opposite trend was observed in the ICD-low subtype (Figures 4D, E). Here, CD4 is linked to head and neck squamous cell carcinoma.