Our study found that elevated CCL25 levels were significantly associated with increased GBM risk (OR = 1.24, 95% CI = 1.02–1.51), echoing recent research on chemokines’ roles in the tumor microenvironment.[36] CCL25 may act by recruiting CCR9-positive immune cells to the tumor microenvironment, including regulatory T cells and myeloid-derived suppressor cells, thereby promoting the formation of an immunosuppressive microenvironment. This evidence concerns the gene CCR9 and glioblastoma.