IL15 and glioma: To evaluate the effects of Ad5-Ki67/IL-15 on PD-L1 expression in glioma cells, different glioma cells GL261, U251, U87 and BT-01, respectively, cocultured with GA-MSCs with the virus for 24 h, 48 h and 72 h, we confirmed that the virus has the potential to overcome GA-MSCs to effectively kill glioma cells (Fig. 5A–D).