extremely significantP < 0.0001
In pan-cancers, GPR18 mRNA expression levels demonstrated extremely significant Pearson correlations (Pearson R values) with MS4A1 and TIL-B levels across all 29 cancer types, except for DLBC and UVM ( R > 0.2, P < 0.0001; Fig. 4b , Supplementary Fig. 4 ).