In accordance with the hypotheses that plasma membrane-associated presentation is the major factor determining agonistic activity of conventional αCD40- and α41BB antibodies, we and others recently reported anchoring-dependent agonism of αCD40- and α41BB antibody fusion proteins carrying an anchor domain specific for plasma membrane-exposed tumor marker proteins, such as CD20 12, BCMA 13, FAP 23 or mesothelin 24. Here, MSLN is linked to neoplasm.