CAR T cell = Chimeric Antigen Receptor T cell. Chimeric antigen receptors (CARs) are receptor proteins that have been engineered to give T cells the new ability to target a specific antigen. The receptors are chimeric in that they combine both antigen-binding and T cell activating functions into a single receptor.

CAR T cell therapy uses T cells engineered with CARs to treat cancer. The premise of CAR-T immunotherapy is to modify T cells to recognize cancer cells in order to more effectively target and destroy them. Scientists harvest T cells from people, genetically alter them, then infuse the resulting CAR T cells into patients to attack their tumors.

1. T cells are isolated from a patient’s blood.
2. A new gene encoding a chimeric antigen receptor is incorporated into the T cells.
3. Engineered T cells are now specific to a desired target antigen.
4. Engineered T cells are expanded in tissue culture.
5. Engineered T cells are infused back into the patient.

Source: CAR T cell – Wikipedia

Here is a good review:

CAR T-cell Therapy and Its Side Effects | American Cancer Society