GZMB and neoplasm: Second, compared with current clinical imaging methods (such as CT, MRI, and 18F-FDG PET/CT used for noninvasive monitoring of ICI therapy), which take 4–8 weeks to confirm the presence of PD (8), 68Ga-grazytracer PET can identify granzyme B release upon immunotherapy, facilitating early prediction of tumor responses to therapy and early identification of pseudoprogression.