CD8A and neoplasm: Previous studies have demonstrated that monocytes, stimulated by a certain TME, are polarized into the M2 macrophages and secrete anti-inflammatory cytokines such as interleukin-8 (IL-8), interleukin-10 (IL-10), and transforming growth factor beta (TGF-β), which participate in angiogenesis, inflammation, and matrix remodeling, thereby inducing the apoptosis of CD8+ T cells, inhibiting T helper 1 (Th1) immune response, and reshaping the TME to promote tumor growth, invasion, and metastasis (Galdiero et al., 2013; Yu et al., 2018; Ovais et al., 2019).