The combination of elexacaftor/tezacaftor/ivacaftor (ETI, Trikafta) reverses the primary defect in cystic fibrosis (CF) by improving CFTR-mediated Cl− and HCO3− secretion by airway epithelial cells (AECs), leading to improved lung function and less frequent exacerbations and hospitalizations. This evidence concerns the gene CFTR and cystic fibrosis.