In this issue of JEM, Hosokawa et al. (https://doi-org.proxy.insermbiblio.inist.fr/10.1084/jem.20190972) establish that transcription factor Bcl11b regulates almost completely distinct sets of genes in T cell precursors and ILC2s. To understand how this occurs, they identify multiple levels of functional regulation for Bcl11b that are used differently by T cell precursors and ILC2s.