Recent Advances in Fluorescence Probes for Real-Time Imaging of Cancer Immunotherapy

Abstract Immunotherapy has emerged as a transformative paradigm in cancer treatment, significantly improving long-term patient survival rates. However, the relatively low immune response rate remains a primary obstacle to achieving precision oncology, necessitating the timely and accurate assessment of immunotherapy efficacy. Fluorescence molecular imaging has proven to be a powerful analytical tool, enabling the noninvasive tracking of immune cells and facilitating the highly sensitive and specific detection of early-stage biomarker fluctuations. This noninvasive visualization capability not only allows for accurate efficacy evaluation but also provides critical insights for the dynamic adjustment of treatment strategies. This review comprehensively summarizes recent advances in fluorescence molecular probes designed for the real-time monitoring of cancer immunotherapy and discusses their potential in predicting treatment prognosis. Specifically, we systematically outline the design logic and working mechanisms of both “always-on” (active targeting) and “activatable” (environment-responsive) fluorescence imaging probes, detailing their applications in monitoring immune responses throughout the immunotherapy cycle. Finally, we address the current challenges in developing and applying molecular probes for real-time cancer immune activation imaging.