CD8A and neoplasm: The tumor microenvironment (TME) contains a plethora of immune cells (i.e., macrophages, neutrophils, mast cells, eosinophils, CD8+ and CD4+ T cells, etc.)which produce a multitude of mediators that promote cell proliferation, angiogenesis, lymphangiogenesis, and the formation of metastasis [163,164,165].