Pseudomonas aeruginosa is a leading cause of chronic lung infections in cystic fibrosis (CF) patients. While bacteriophages hold potential as a treatment for antibiotic-resistant infections, the complex structure and heterogeneity of P. aeruginosa biofilms pose significant challenges to phage therapy. In this study, we investigate the adaptive evolution of the Pbunavirus phage PE1 to biofilms formed by a CF-der...