Conflict of interest: M. Kolb is site PI in industry-sponsored clinical trials for Roche and Boehringer Ingelheim, and reports grants from Canadian Institute for Health Research, grants and personal fees for advisory board work from Boehringer Ingelheim and Roche Canada, personal fees for advisory board work from Horizon, Algernon, CSL Behring, DevPro, Bellerophon and BMS, personal fees for adjudication committee work from United Therapeutics, personal fees for data monitoring committee work from LabCorp, and a chief editor allowance from the European Respiratory Society, outside the submitted work. B. Crestani reports grants or contracts from BMS, Boehringer Ingelheim and Roche, consultancy fees from Apellis, payment or honoraria for lectures, presentations, speakers' bureaus, manuscript writing or educational events from Boehringer Ingelheim, BMS, Roche, Sanofi, Novartis, AstraZeneca and Chiesi, and receipt of equipment, materials, drugs, medical writing, gifts or other services from Translate Bio.