Chimeric antigen receptor (CAR) T cell immunotherapy shows great promise as a treatment for cancer and other diseases. CAR-T cells are patient-derived T cells engineered to express an antigen receptor that is specific for the patient’s tumor cells. While there has been some clinical success with CAR-T therapy, researchers still face challenges in optimizing its effectiveness, for example when applying it to solid tumors, and in addressing safety concerns such as neurotoxicities. Understanding the functional mechanisms and underlying signaling pathways of CAR-T cell activity is crucial to overcoming these challenges. Intensive efforts have been made in recent years to decipher these mechanisms and to elucidate unique signaling pathways in different T cell subpopulations, in order to develop better clinical strategies. This webinar will introduce the audience to the range of different T cell populations and the roles they play in normal immune function as well as disease, and will explain how recent breakthroughs in our understanding of these specialized immune cells can lead to improvements in disease treatment.