IFNG and glioblastoma: Interestingly, the treatment of GBM cells with low PD-L1 with IFN-γ resulted in upregulation of PD-L1 on the cell surface and on the EVs, indirectly confirming importance of PD-L1 in GBM-EVs-mediated immune suppression (Figure 3; Ricklefs et al., 2018).