Abstract: The application of immunotherapy (IMT), especially immune checkpoint inhibitors (ICI), has brought revolutionary breakthroughs to cancer treatment, but only a few patients (about 10% to 30%) have shown a long-term response to the single therapy of immunotherapy. In therapeutic alliance, different drugs play a complementary or synergistic role, showing great potential. However, the therapeutic response rate of combined drugs varies greatly, and it may be accompanied by serious side effects while improving the therapeutic effect. Therefore, in order to use these treatments with good application prospects safely, effectively and widely, more research is needed. It is convincing that Immuno-positron emission tomography (ImmunoPET) is a useful tool for the development and the clinical transformation of therapeutic alliance. The author introduces several specific biomarkers that can be used to monitor immune activation, outline the latest progress of ImmunoPET′s exploration of cancer therapeutic alliance, and discuss the implementation direction of this type of imaging method in preclinical and clinical aspects in the future.