Correction to: Nature Immunology https://doi.org/10.1038/s41590-017-0006-x (2018); published online 14 December 2017.

In the version of this Review initially published, the type of cell in the final sentence of the legend to Fig. 3 (group 2 innate lymphoid cells) was incorrect. The correct type of cell is group 3 innate lymphoid cells. The error has been corrected in the HTML and PDF versions of the article.