TYR and neoplasm: Similar to bacteria, bacterial OMVs can be used to PTT by stimulating the secretion of tumor‐associated cytokines and cause the extravasation of red blood cells within the tumor, which led to significantly darker tumors.[215, 218] Encapsulating the biopolymer melanin in E. coli OMVs expressing tyrosinase transgenes (OMVMel) could not improve the photothermal properties of melanin, but also enhance immunotherapy (as shown in Figure 13D).[219] Zhai et al.