reported that an engineered attenuated S. typhimurium strain could successfully suppress the tumor growth and metastasis in murine colon and melanoma models through a secretion of Vibrio vulnificus flagellin B (FlaB) (Figure 6).[57] The underlying mechanism can be interpreted in the following manner: TLR4 signaling is a key to suppress tumor growth by inducing the activation and infiltration of immune cells mediated by FlaB‐secreting bacteria, whereas TLR5 signaling is capable of augmenting the host reactions. Here, TLR4 is linked to melanoma.