Professor Susan Kaech is currently Professor of Immunobiology in the Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA. Her laboratory aims to understand how memory T cells are generated during infection and vaccination, and why, in some circumstances, an immunization fails to induce long-term T cell immunity. They are also learning how T cells are regulated in tumor microenvironments to better understand how their functions become suppressed as they infiltrate tumors in order to develop new methods of immunotherapy that enhance anti-tumor responses. Using several powerful model systems of infection or cancer in mice, they are elucidating mechanisms involved in the development of protective and long-lived memory T cells that form after acute infection or conversely, of dysfunctional or “exhausted” T cells that form in tumors or during chronic viral infections. Their studies are aimed at identifying the signaling and metabolic pathways that regulate the differentiation of T cells in these different types of environments so that we can design new ways to optimize the formation of highly functional, protective memory T cells to fight infection and cancer.