CD8A and neoplasm: A [89Zr]ZrDFO‐Cys‐diabody has recently been developed for tracking endogenous CD8+ T‐cells which could be used to evaluate the tumour immune response of novel immunotherapies.85 The Cys‐diabody was conjugated to a maleimide‐DFO via the engineered C‐terminal cysteine of the fragment and labelled with 89Zr in high RCY.