The other 'cool' part about CARs is that 'without much modification' is not near so large a challenge as it is for small molecules. Certainly there are regulatory barriers, but scientifically, the ease with which you could just (genetically) pop on a custom nanobody/binding domain is many many orders of magnitude less than trying to find a small molecule to hit a different target.

In a decade or two, I wouldn't be surprised if CARs were being deployed that were entirely customized to a patient's cancer, where the scaffolding was 'FDA approved', while the binding domain was cultured to specifically react to this patient's cancer, encoded into DNA, printed and designed within the space of a few hours or days. The kind of customizability that comes from a genetic therapy opens a lot of new doors.