The invention relates to chimeric antigen receptor (CAR) scaffolds comprising: a target binding domain a spacer region a transmembrane domain and an intracellular effector domain, wherein the spacer region comprises at least one, or multiples of, domains 2, 3 or 4 or a combination thereof of a CD4 molecule. The invention also relates to polynucleotides and expression vectors encoding said CAR scaffold and immunomodulatory cells comprising said CAR scaffold. The invention also relates to methods of engineering an immunomodulatory cell to comprise said CAR scaffold
