Research has reported that EGF could induce STAT1 expression to exacerbate the IFN-γ-mediated PD-L1 axis in EGFR-positive cancer cell lines, excluding glioma, and blockade of EGFR by afatinib inhibited EGF- and IFN-γ-mediated PD-L1 expression [42]. Here, EGFR is linked to glioma.