THE PRESENT DISCLOSURE PROVIDES ISOLATED BINDING MOLECULES THAT BIND TO HUMAN 4-1BB, NUCLEIC ACID MOLECULES ENCODING AN AMINO ACID SEQUENCE OF THE BINDING MOLECULES, VECTORS COMPRISING THE NUCLEIC ACID MOLECULES, HOST CELLS CONTAINING THE VECTORS, METHODS OF MAKING THE BINDING MOLECULES, PHARMACEUTICAL COMPOSITIONS CONTAINING THE BINDING MOLECULES, AND METHODS OF USING THE BINDING MOLECULES OR COMPOSITIONS.