CD8A and cancer: The TME consists of a heterogeneous population of cells including the stromal cells, and the extracellular matrix components (non-cellular), cancer cells, immune lymphoid cells (CD8 T cells, CD4 T cells, Tregs, NK cells, B cells), macrophages (M1) and tumor associated macrophages (M2), myeloid derived suppressor cells (MDCS), neutrophils, cancer-associated fibroblast cells and endothelial cells.