To investigate the effects of DEX on PD-L1 and GILZ protein expression in glioblastoma, we treated two human glioblastoma cell lines—U251 and U87—with increasing concentrations of DEX (10−6 M, 10−7 M, and 10−8 M) for 24 and 48 h. The gene discussed is CD274; the disease is glioblastoma.