The stimulatory effect of normoxic tumor-derived ExVs on γδ T-cell activity was not observed with hypoxic tumor-derived ExVs that, in contrast, increased the suppressive effect of myeloid-derived suppressor cells (MDSCs) on γδ T cells through regulating the miR-21/PTEN/PD-L1 axis. This evidence concerns the gene PTEN and neoplasm.