This study unveils distinct T‐cell intrinsic roles of RelA and RelB in NF‐κB family members, for RelA in accessory thymocytes and RelB in thymic γδ‐T cell progenitors, as specific requirements to provoke peripheral T cells to rapidly produce IL‐17/γIFN, reoriginating peripheral‐immune axis to fight EMT/CSC subsets or other biological burdens such as bacterial infections. This evidence concerns the gene RELB and bacterial infectious disease.