To expand a little on what you’re saying, in this procedure, T-cells are genetically engineered “to make proteins on their surface called chimeric antigen receptors (CARs). The CARs can recognise and target a specific protein on the surface of the cancer cells.” (source: https://www.cancerresearchuk.org/about-cancer/treatment/targeted-cancer-drugs-immunotherapy/car-t-cell-therapy)