In the areas of bioimaging and detection, biosensors have attracted extensive attention recently. Specifically, biosensors based on nanostructures provide a more sensitive detection due to their prominent properties. Different biosensors have used quantum dots (QDs) due to their unique properties, like high quantum yield (QY) and photoluminescence. In addition to possessing the advantages of common QDs, carbon quantum dots (CQDs) have a higher solubility, lower toxicity, and easier synthesis, making them highly useful and a promising candidate for biomedical applications. The CQD is a zero-dimensional nanostructure with a size of less than 10 nm in every dimension. The unparallel features of CQDs, including good biocompatibility and unique optical properties, like high photoluminescence (PL) and Quantum yield (QY), make them attractive candidates for biosensor and bioimaging applications. This review examines the recent advances in biosensors based on CQDs and presents the properties, challenges, and future perspectives to pave the way for further studies in the future.