Inhaled recombinant human GM-CSF (sargramostim, molgramostim) has recently emerged as a successful strategy for driving a beneficial AM phenotype and improving barrier function in pneumonia-associated acute respiratory distress syndrome, including COVID-19 (193–196), with the first phase II trials revealing encouraging results and a beneficial safety profile (ClinicalTrials.gov NCT02595060, NCT04569877). This evidence concerns the gene CSF2 and COVID-19.