IL17A and neoplasm: It is generally known that TGF‐β is essential in producing pTregs, iTregs, and some TH17 cells,217, 218 and the above findings have demonstrated that Th17 (IL‐17A+FOXP3−) cells progressively transdifferentiate into IL‐17A+FOXP3+ and ex‐Th17 IL‐17A−FOXP3+ T cells promoted by TGF‐β during tumor progression, which are subpopulations of suppressive Tregs (Figure 2).