CCL19 and neoplasm: More recently, the fourth‐generation CAR‐T cells, also called TRUCK‐T (CAR redirected T cells that deliver a transgenic product to the targeted tumour tissue) cells, were engineered to secrete specific cytokines, such as IL‐12, IL15, IL‐18, CCL19 and IL‐7, so as to overcome the suppression from the tumour immune microenvironment, recruit and activate the second wave of immune cells to produce an immune response.19