In Braf/Pten melanoma-draining LNs, TSLP promoted not only GATA3+ Th2 cells, but also GATA3+ Tregs expressing a specific signature including ST2, CCR8, ICOS, PD-1, CTLA-4, OX40, and IL-10 — but not Th2 cytokines IL-4 and IL-13. Here, ICOS is linked to melanoma.