Moreover, M1 macrophage-derived exosomes (M1-Exos) delivering anti-PD-L1 siRNA effectively reduce PD-L1 expression in tumors, increase CD8+ T cell infiltration, and promote macrophage repolarization from the immunosuppressive M2 to the pro-inflammatory M1 phenotype, inhibiting tumor growth [266]. The gene discussed is CD8A; the disease is neoplasm.