IL17A and gastric cancer: Surprisingly, in addition to CD4_C6_IL17A (Th17), we found that the CD8_C8_IL17A cluster also highly expressed several known classical markers of Th17 cells, such as IL17A, RORC (RORγt), and IL23R. We observed that CD8+IL17+ T cells constituted more than 1% of the total tumor infiltrated T cell population in 8 out of the 10 patients (Supplementary Fig. 6g), and the presence of CD8+IL17+ T cells in the TME of GC were subsequently confirmed by multicolor IHC staining (Fig. 5d and Supplementary Fig. 6e).