Different from traditional tumor treatment methods

immunotherapy is to fight tumors through the autoimmune system. In recent years

immune checkpoint inhibitors (ICI) have proven to be a promising immuno-oncology therapy method

and have been successfully applied to the treatment of many malignancies in the clinic. However

identifying patients who may benefit from ICI therapy remains extremely challenging. Molecular imaging techniques that enable non-invasive

real-time detection

visualization of lesions and

in vivo distribution play an important role in tumor staging

disease dynamic monitoring

and screening of ICI treatment beneficiaries through different radionuclide-labeled ICI as tracers. This review summarized the targeted molecular imaging probes of clinical immune checkpoints ［programmed death 1 (PD-1)/ programmed death ligand 1 (PD-L1) and cytotoxic T lymphocyte- associated antigen-4 (CTLA-4)］ and emerging immune checkpoints ［T cell immunoglobulin and mucin domain-containing protein 3 (TIM3) and lymphocyte activation gene-3 (

LAG

-3)］

analyzed the application of these ICI in tumor treatment

analyzed the limitations of immune checkpoint research

and looked forward to the future research direction of ICI and molecular imaging.