CFTR and cystic fibrosis: While the clinical development of small‐molecule CFTR modulators that are applied systemically, enter airway cells via the basolateral membrane and act on the CFTR protein inside the cells was highly successful, previous attempts to modulate ion channel activity with inhaled drugs that have to engage with their target at the apical surface, such as the P2Y2 receptor agonist denufosol or inhibitors of the epithelial sodium channel ENaC, failed in clinical trials in CF (Graeber & Mall, 2023; Mall, 2020).