Illustration of a dendritic cell (white) presenting antigens to a chimeric antigen receptor (CAR) T cell (blue). CAR-T cells are a patient's own T cells, a form of white blood cell, that have been genetically modified to recognise and destroy certain cancer or autoimmune cells that might otherwise be tolerated by the immune system. Dendritic cells express markers from faulty cells or pathogens (antigens) that other white blood cells can then recognise and respond to.