AIF1 and glioblastoma: Fe3O4-siPD-L1, Fe3O4-siPD-L1@M-BV2 and Fe3O4-siPD-L1@M-BV2 + magnet significantly increased the number of Iba-1+CD16/32+ cells (M1 type microglia) in drug-resistant GBM tissue in comparison with normal saline and Fe3O4-siNC.