BACKGROUND: Insufficient T-cell infiltration in tumours causes immune checkpoint inhibitor (ICI) resistance in glioblastoma (GBM) patients. The aim of this study was to demonstrate a preferable way to facilitate T-cell infiltration and improve the therapeutic effects of ICIs in GBM. METHODS: Flow cytometry, western blot and immunofluorescence staining were used to detect the effects of ATP11B upregulation on S1PR1 expression and distribution, T-cell infiltration and differentiation. A coculture system and an intracranial GBM model were established to explore the anti-GBM potential of ATP11B/S1PR1 signaling through systemic administration of CD3-DSPE-PEG2K-NHS/ATP11B nanoparticles to specifically deliver ATP11B overexpressing plasmids to T cells. RESULTS: S1PR1 deficiency in T cells caused T-cell lymphopenia and systemic immunosuppression in GBM, whereas ATP11B overexpression induced the upregulation and externalization of S1PR1 on T-cell membranes, thus increasing the ability of T cells to eliminate GBM cells. In intracranial GBM models, an ATP11B overexpression plasmid was specifically delivered to T cells in the peripheral blood, bone marrow and spleen, then triggering the infiltration of T cells deeply into the GBM and reversing systemic immunosuppression, ultimately enhancing the therapeutic outcomes of ICIs. CONCLUSIONS: The upregulation and externalization of S1PR1 on T cells mediated by ATP11B overexpression may be promising immunotherapeutic alternatives for GBM treatment.