FOXP3 and chronic obstructive pulmonary disease: Wuwei Xiaodu Drink regulates Foxp3 expression via the IL-2/STAT5 signaling pathway (Huang K. et al., 2022), Bufei Yishen formula induces Treg differentiation by increasing STAT5 phosphorylation levels, upregulating Foxp3 gene expression, and correcting the Th17/Treg imbalance, which in turn improves lung function and alleviates inflammation in chronic obstructive pulmonary disease rats (Peng et al., 2018).