A trispecific inhibitor for treating cancer includes a first targeting domain having a binding specificity conferred by a VEGF binding antagonist; a second targeting domain having a binding specificity conferred by an immune checkpoint regulator binding antagonist; and a third targeting domain having a binding specificity conferred by a Tie2 tyrosine kinase receptor binding antagonist. The targeting domains may contain one or more antibody variable regions, peptide inhibitors, dominant negative proteins, small molecule drugs or combinations thereof.