Magneto-optical nanosystems combine magnetic and optical properties to enhance multimodal imaging and therapy for tumors. These systems offer advantages such as high spatial resolution, sensitivity, and the ability to guide targeted treatments. Recent advancements in magneto-optical nanosystems have enabled precise tumor diagnosis and treatment through multimodal imaging techniques like MRI, FLI, PAI, and MPI. These systems are composed of magnetic nanoparticles (MNPs) and optical materials, such as iron oxide, Gd, Ni, Co, and Mn-based nanoparticles, combined with various optical nanomaterials like quantum dots, carbon dots, graphene, and lanthanide-doped nanoparticles. These systems can be tailored for specific applications, including tumor targeting, drug delivery, and photothermal therapy. For example, magneto-optical nanosystems with core-shell structures, such as QD@MHS NPs and HMNS/SiO2/GQDs, exhibit enhanced stability and functionality. Additionally, systems incorporating gold or silver nanoparticles with magnetic properties can improve photothermal conversion efficiency. Organic fluorescent dyes and other biocompatible materials are also integrated to enhance versatility and reduce toxicity. These nanosystems have shown promise in clinical applications, including real-time tumor imaging, targeted drug delivery, and enhanced therapeutic outcomes. Future research aims to further optimize these systems for broader biomedical applications.Magneto-optical nanosystems combine magnetic and optical properties to enhance multimodal imaging and therapy for tumors. These systems offer advantages such as high spatial resolution, sensitivity, and the ability to guide targeted treatments. Recent advancements in magneto-optical nanosystems have enabled precise tumor diagnosis and treatment through multimodal imaging techniques like MRI, FLI, PAI, and MPI. These systems are composed of magnetic nanoparticles (MNPs) and optical materials, such as iron oxide, Gd, Ni, Co, and Mn-based nanoparticles, combined with various optical nanomaterials like quantum dots, carbon dots, graphene, and lanthanide-doped nanoparticles. These systems can be tailored for specific applications, including tumor targeting, drug delivery, and photothermal therapy. For example, magneto-optical nanosystems with core-shell structures, such as QD@MHS NPs and HMNS/SiO2/GQDs, exhibit enhanced stability and functionality. Additionally, systems incorporating gold or silver nanoparticles with magnetic properties can improve photothermal conversion efficiency. Organic fluorescent dyes and other biocompatible materials are also integrated to enhance versatility and reduce toxicity. These nanosystems have shown promise in clinical applications, including real-time tumor imaging, targeted drug delivery, and enhanced therapeutic outcomes. Future research aims to further optimize these systems for broader biomedical applications.