The interactions of CD15+ neutrophils with CD4+ T cells in GC tumor tissues (Figure 5A; Figure S7A), the positive correlations between neutrophils and CD4+ T cells in GC tumor tissues (Figure S7B), and the significant positive correlations between the levels of IL‐17A and B7‐H2+ neutrophils in GC tumor tissues (Figure 5B) imply that tumoral neutrophils may promote IL‐17A‐producing Th subset polarization via B7‐H2. This evidence concerns the gene ICOSLG and gastric cancer.