By using radiolabeled antibodies like [89Zr]Trastuzumab, targeting HER2, [89Zr]Zr-TLX250, targeting hypoxia or ICIs like [89Zr]Zr-atezolizumab, targeting PD-L1 or immuno-PET can provide valuable insights into the immune response within the tumor as well as the TME and help optimize immunotherapy strategies. The gene discussed is ERBB2; the disease is neoplasm.