ABSTRACT CD8 T cells control live replicating viral infections, but most licensed vaccines do not efficiently generate protective memory CD8 T cells. Recent evidence suggests that developing vaccines that establish memory CD8 T cells may be the solution to controlling or preventing historically recalcitrant pathogens. Tissue-resident memory CD8 T cells (TRM), which occupy many tissues of the body without circulating and persist long term, have a vital role in tissue immunosurveillance. TRM are also increasingly thought to mediate allergic and autoimmune responses and transplant rejection. TRM were only recently discovered, and thus there are substantial gaps in our understanding of the mechanisms by which TRM achieve anti-viral immunity and contribute to immunopathology. If future vaccination and therapy strategies are to successfully leverage CD8 TRM for protection against pathogens or reducing immunopathology, fundamental questions on how TRM are generated and maintained in tissue need to be addressed. I recently compared the transcriptional programs of TRM populations with recirculating T cell subsets and CD8 T cell populations that transiently express the imperfect TRM marker CD69 in response to recent TCR stimulation or inflammation. I also developed an original approach and workflow to identify tissue specific TRM phenotypes. Through Aim 1 I will further expand our knowledge of shared and tissue specific CD8 TRM transcriptional and phenotypic signatures. I will also validate tissue specific phenotypes via flow cytometry, parabiosis studies, and the use of `dirty' mice that contain CD69+ T cells within the equilibrating T cell population. Through Aim 2 I will apply a CRISPR/Cas9 gene editing approach that I have established to evaluate the role of several exhaustion genes in the ontogeny, differentiation and maintenance of TRM. Further elucidation of how tissue-resident memory T-cell populations are generated and maintained in peripheral tissues and the role they play in immune responses in tissue will assist in the design of prophylactic vaccines and may also inform the development of therapies that treat intractable infections or disease.