For example, BCMA is essential for the survival of multiple myeloma cells,[62] and CD22‐deficient B cells exhibit reduced proliferation and enhanced turnover rates.[63] This property makes us confident that, while our prototype design is currently only tested on targeting CD19 in B‐ALL, our technology and strategies can be easily adapted to target many other types of tumors by substituting the CD19‐scFv with another antigen‐targeting module. Here, CD19 is linked to acute lymphoblastic leukemia.