Correction to: Nature Immunology 18, 800–812 (2017); https://doi.org/10.1038/ni.3748; published online 15 May 2017.

In the version of this article initially published, the institution name for affiliation 3 (Maryland Anderson Cancer Center) was incorrect. The correct institution is MD Anderson Cancer Center. The error has been corrected in the HTML and PDF versions of the article.