ONLINE COVER Rejuvenation Potential of T_RM Subsets. This month’s cover depicts a “fountain of youth” from which new tissue resident memory T cells (T_RM) are emerging after a secondary infectious challenge. Newly formed CD103^– T_RM (blue) and CD103⁺ T_RM (red) are derived from proliferating, CD103^– precursor cells and join the pool of preexisting CD103⁺ T_RM (gray) that lack this restorative capacity. This model for T_RM replenishment is supported by new fate-mapping mouse models described in separate papers by von Hoesslin and Kuhlmann et al. and Fung et al. that are discussed in a Focus by Jensen and Farber.