Bintrafusp alfa is a first-in-class bifunctional fusion protein composed of the extracellular domain of the human TGF-β receptor II (a TGF-β “trap”) fused via a flexible linker to the C terminus of each heavy chain of an IgG1 antibody blocking PD-L1, which might allow for simultaneous inhibition of TGF-β and PD-L1 in the tumor microenvironment.6 In a phase I study (NCT02517398), bintrafusp alfa has shown early signs of clinical efficacy and a manageable safety profile in patients with heavily pretreated solid tumors.7 Here, we report results from an expansion cohort of this phase I study. Here, TGFB1 is linked to neoplasm.