It is urgent to select patients who will benefit from immunotherapy, so as to help the clinicians adjust the regimens and avoid unnecessary side effect. 18F-G1 is a new radioactive tracer targeting granzyme B, holding great promise in assessing early response to immunotherapy. This study will explore the safety of 18F-G1 PET/CT in patients with solid tumors and hematological tumors receiving immunotherapy, analyze its imaging features, and assess its efficacy in predicting early immunotherapy response and prognosis, so as to aid the clinicians in precise patient stratification and regimen adjustment.