CD4 and neoplasm: To elucidate how EGCG acts on the immune microenvironment, we reviewed its immunoregulatory roles and relevant molecular targets in various immune cells in TME, including CD8+/CD4+ T cells, natural killer (NK) cells, dendritic cells (DCs), myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs), tumor-associated macrophages (TAMs), and tumor-associated neutrophils (TANs) (Figure 1).