While all four mAbs enhanced the in vivo immune response, CRD2- and CRD4-binding instead of CRD1-binding anti-mOX40 mAbs showed the highest levels of in vivo agonistic activities in terms of stimulating CD8 Teff cell expansion and anti-tumor activity, highlighting that it remains unknown how the binding epitope affects the intrinsic agonistic potential of mAbs (Zhang et al., 2019). Here, CD8A is linked to neoplasm.