Abstract: Provided herein is a model, in particular a mouse model, for assessing or evaluating toxicity to an immunotherapy, for example a therapeutic cell therapy, such as a cell therapy containing engineered cells, such as T cells, expressing a recombinant receptor, e.g. a chimeric antigen receptor (CAR). Also provided is a method for generating the mouse model. Also provided herein are methods of use for the mouse models of toxicity, such as to evaluate modified or alternative immunotherapies, and/or to evaluate test agents, including agents to assess as potential interventions to reduce, prevent, or ameliorate toxicity to immunotherapy in human subjects and/or for use in combination with an immunotherapy, e.g. CAR?T cell therapy.