CD4 and neoplasm: From a histological perspective, the TME consists of: (a) immune cells such as tumor-associated macrophages (TAM), natural killer (NK) cells, neutrophils, mast cells, dendritic cells (DC), CD4+ and CD8+ T cells, and B cells; (b) vascular cells including microvascular cells, endothelial cells (EC), and pericytes; (c) extracellular matrix molecules including collagen, glycoproteins, and proteoglycans; and (d) nonmalignant cells of mesenchymal origin such as fibroblasts, mesenchymal stromal cells (MSC), and cancer-associated fibroblasts (CAF) [3] (Figure 1a).