TGFB1 and chronic obstructive pulmonary disease: In recent years, transforming growth factor-β1 (TGF-β1), a pleiotropic cytokine, has been recognized to play a critical role in the airway remodeling process of chronic respiratory diseases such as asthma, COPD, and pulmonary fibrosis (Hamidi et al., 2017; Li Y. et al., 2024).