There is disclosed compositions and methods relating to or derived from anti-LAG3 antibodies. More specifically, there is disclosed fully human antibodies that bind LAG3, LAG3-antibody binding fragments and derivatives of such antibodies, and LAG3-binding polypeptides comprising such fragments. Further still, there is disclosed nucleic acids encoding such antibodies, antibody fragments and derivatives and polypeptides, cells comprising such polynucleotides, methods of making such antibodies, antibody fragments and derivatives and polypeptides, and methods of using such antibodies, antibody fragments and derivatives and polypeptides, including methods of treating a disease.
