PDCD1LG2 and glioma: Besides, we discovered that CCL22, CD163, CLEC7A, CLEC10A, CSF1R, FCGR3A, PTPRC, IRF1, PDCD1LG2, PDGFB, PPARG, IL-10, STAT6, TGFB1, IL23A and IRF4 of the M2 macrophage markers were found to have a positive correlation with LILRB1 expression in glioma (Additional file 1: Supplementary Figure S5A-P).