Correction to: Nature Reviews Immunology https://doi.org/10.1038/s41577-023-00943-0, published online 4 October 2023.

In the version of the article initially published, in the “NK cells” section, the phrase “in the per protocol analysis only” was missing from the end of the sentence “This revealed increased NK cell infiltration in the exercise group compared to the control group”. The error has been corrected in the HTML and PDF versions of the article.