In Fig. 2a of this Letter, owing to an error during the production process, the y-axis label of the right-most graph was incorrectly shown as ‘No. of ILC3s per lung (×103)’ instead of ‘No. of ILC3s per lung (×102)’. In addition, author Marco Colonna was inadvertently associated with affiliation 7 (Division of Allergy, Immmunology and Rheumatology, Department of Medicine, University of Rochester Medical Center, Rochester, NY, USA) instead of affiliation 9 (Division of Immunobiology, Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA). These errors have been corrected online.