CD4 and gastric cancer: The main subsets of T cells that show infiltration into the TME in gastric cancer scRNAseq datasets include CD4+ T helper cells (Th, co-expressing CD4), CD8+ cytotoxic T lymphocytes (CTL, co-expressing CD8A), regulatory T cells (Treg, co-expressing FOXP3), and natural killer T cells (NKT, co-expressing NKG7) (20, 22, 26, 39).