A fundamental feature of the immune system is the ability to maintain immune homeostasis. Loss of tolerance to self or innocuous foreign antigens can result in autoimmune diseases or transplant rejection, respectively. On the other hand, inappropriate tolerance to antigens such as those present in tumor cells or viruses, can result in loss of tumor immunity or an inability to resolve infectious diseases. Immune responses are tightly regulated at the molecular level, through cellular interactions, and by the microenvironment. Identifying these mechanisms offers the potential to develop more precise immunotherapies for a wide range of dysregulated immune responses. The Crome Lab is focused on delineating regulatory mechanisms which control T cell responses, with a particular focus on innate lymphoid cells and regulatory T cells.