STAT3 and central nervous system cancer: Activation of ALK/STAT3 in T cell lymphoma [5], AP-1/JAK/STAT in classical Hodgkin lymphoma (cHL) [6], the microRNA-200/ZEB1 axis in non-small-cell lung cancer (NSCLC) [7], c-jun/STAT3 in BRAF inhibitor-resistant melanoma [8], and PI3K in glioma [9] have each been reported to upregulate PD-L1 expression on tumor cells.