PDCD1 and neoplasm: Intravenous injection of the resulting extracellular vesicles to CT26 tumor-bearing mice (colon carcinoma) resulted in downregulation of PD-L1 in tumor tissues, disruption of PD-1-PD-L1 interaction, an increased amount of CD8+ cells, and an elevated M1/M2 ratio, mediated by an increase in the IFNγ level, and, consequently, a significantly increased survival of mice.