Abstract
T cell development and remodeling during aging are crucial for immune health in late life and human healthspan. In this review, we delve into the mechanisms underlying these processes, with a focus on thymus development and involution, and their implications in immune function for older adults. We examine T cell subset development, including conventional naïve and regulatory T cells, effector and memory subsets, and unique subsets like γδ T cells, mucosal-associated invariant T (MAIT) cells, and natural killer T (NKT) cells. Our insights highlight the importance of enhancing immune function in older individuals and suggest potential strategies for overcoming the obstacles in studying T cell development and aging.