The present invention provides a cell which co-expresses a first chimeric antigen receptor (CAR) and second CAR at the cell surface, each CAR comprising:(i) an antigen-binding domain；(ii) a spacer(iii) a trans-membrane domain； and(iv) an endodomainwherein the antigen binding domains of the first and second CARs bind to different antigens, and wherein each of the first and second CARs is an activating CAR comprising an activating endodomain.
