The evolving role of tissue-resident memory T cells in infections and cancer

Resident memory T cells (T_RM) form a distinct type of T memory cells that stably resides in tissues. T_RM form an integral part of the immune sensing network and have the ability to control local immune homeostasis and participate in immune responses mediated by pathogens, cancer, and possibly autoantigens during autoimmunity. T_RM express residence gene signatures, functional properties of both memory and effector cells, and remarkable plasticity. T_RM have a well-established role in pathogen immunity, whereas their role in antitumor immune responses and immunotherapy is currently evolving. As T_RM form the most abundant T memory cell population in nonlymphoid tissues, they are attractive targets for therapeutic exploitation. Here, we provide a concise review of the development and physiological role of CD8⁺ T_RM, their involvement in diseases, and their potential therapeutic exploitation.