CD8A and neoplasm: In the EMT6 tumor-bearing mice, the population and cytotoxicity of the CD8+ T cells were decreased in the EV injection group (MAC + anti-PD-L1 + EV) more than the combination therapy group (MAC + anti-PD-L1), whereas injection with EVs blocked with anti-PD-L1 antibody (MAC + anti-PD-L1 + EV blocked by anti-PD-L1), displayed no significant changes (Figure 5D).