Vilanterol is a long-acting selective β2-adrenergic receptor agonist (LABA) that relaxes airway smooth muscle by stimulating β2 receptors, increasing cyclic AMP, and promoting bronchodilation. Fluticasone furoate is a potent inhaled corticosteroid (ICS) that binds glucocorticoid receptors, reducing airway inflammation via suppression of inflammatory gene expression and mediator release. The combination produces complementary effects: vilanterol provides sustained bronchodilation, while fluticasone furoate controls airway inflammation, improving airflow and symptom control in asthma and COPD.