Peng et al. developed a dual-lockedNIR fluorescence-based sensor for selective marking of melanoma cells,applying peroxide tyrosinase cascade activation of a fluorescence-inactivemethylene blue borate derivative.39 Whilethis probe was proven effective for in vivo tumor visualization, itpossesses some limitations from the perspective of individual H2O2 and tyrosinase detection, as only the copresenceof both analytes results in the desired fluorescence response. Here, TYR is linked to melanoma.