Rejuvenation of elementary immune system components has emerged as a promising strategy to deal with increased susceptibility to infections, cancers, autoimmune disorders, and low efficacy to vaccines, frequently accompanying aging. In this context, the thymus has gained significant attention. A recent study by Santamaria et al. reveals that the receptor activator of nuclear factor-κB (RANK)-RANK ligand (RANKL) axis is altered during age related thymic involution, compromising immune responses. Based on their findings, authors propose exogenous RANKL administration as a therapeutic strategy to reinvigorate thymic function and improve T-cell immunity during aging.