CD8A and cancer: T‐regs are usually related to a suppressive host immune response; these cells were proven to impair proliferation, activation, and effector functions of several immune cell subsets, such as CD8+ and CD4+ T cells, and therefore were related to metastasis and disease progression in different cancer types (Dayan et al., 2012; Song et al., 2016; Weller et al., 2014; Zhang et al., 2019).