In vivo, D-2HG and L-2HG differentially altered ILC subset distribution across mucosal and lymphoid compartments.<h4>Conclusions</h4>IDH1 mutations and their associated oncometabolite D-2HG remodel the innate lymphoid cell landscape in gliomas, driving an ILC3-biased phenotype with reduced checkpoint receptor expression. Here, IDH1 is linked to glioma.