An increased infiltration level due to increased enrichment of immune effector cells was detected in Cluster 2 during the analysis of the TME, such as CD8+ T cells, macrophages, and helper T cells which can act as a protective factor against multiple cancers, such as epithelial ovarian cancer [38], head and neck squamous cell carcinoma [17, 39], and non-small-cell lung cancer [40]. Here, CD8A is linked to head and neck squamous cell carcinoma.