It has been shown that exosomes from cancer cells regulate antitumor immune response by inhibiting T-cell activation and proliferation, inducing regulatory T cells and bone marrow-derived suppressor cells, and suppressing natural killer (NK) and CD8+ T-cell functions (Wieckowski et al., 2009; Pyzer et al., 2016; Whiteside, 2016). Here, CD8A is linked to cancer.