CD4 and cancer: Apart from the tumor cells, the TME consists of the extracellular matrix (ECM) and a variety of other cellular components, such as immune cells (e.g., natural killer cells, dendritic cells, CD4 and CD8 cells, tumor-associated macrophages, myeloid-derived suppressor cells, tumor-associated neutrophils, regulatory B- and T-cells) and stromal cells like cancer-associated fibroblasts (CAFs), cancer-associated adipocytes, endothelial cells, and pericytes.