Immunotherapy has achieved remarkable clinical success in the field of cancer therapy. However

the relatively small fraction of patients who benefit from immunotherapy limits its widespread applications. Accurately identifying patients who would respond to immunotherapy at early stages remains clinically challenging. Therefore

an in vivo method that can noninvasivelycapture information about immune cell/molecule function during immunotherapy and assist in the optimization of immunotherapy strategies is highly desirable. Nuclear medicine and molecular imaging provide a robust tool for the annotation of cancer immune microenvironment through noninvasive visualization of key immune-related biomarkers in vivo in a quantitative manner. This article concisely reviewed the current progresses in nuclear medicine and molecular imaging-guided treatment monitoring for cancer immunotherapy.