Effective T cell responses not only require the engagement of T cell receptors (TCRs, “signal 1”), but also the availability of costimulatory signals (“signal 2”). T cell bispecific antibodies (TCBs) deliver a robust signal 1 by engaging the TCR signaling component CD3ε, while simultaneously binding to tumor antigens. The CD20-TCB glofitamab redirects T cells to CD20-expressing malignant B cells. While glofitamab exhibits strong single agent efficacy, adding costimulatory signaling may …