CD4 and esophageal squamous cell carcinoma: Previous studies on cell types in normal and tumor tissue of ESCC have reported that Activated memory CD4 T cells, M0 macrophages, M1 macrophages, and Neutrophils are significantly found in the tumor tissue, while Eosinophils, Resting mast cells, Monocytes, Gamma delta T cells, Regulatory T cells (Tregs), Plasma cells and Memory B cells were significantly enriched in normal tissue.