According to results from a clinical study of second-generation CEA-CAR-T cells (incorporating a CD28 co-stimulatory domain) in 10 colorectal cancer patients [98], despite using significantly higher doses (1 × 108 cells per kilogram versus 4–6 × 106 cells per kilogram), the best outcome achieved was disease stabilization in 7 of 10 patients. Here, CD28 is linked to colorectal cancer.