Combined therapy, e.g., CTLA-4 and PD-1 checkpoint blockade, is a more effective treatment modality, but in preclinical studies OX40 agonism with CTLA-4 blockade using monoclonal antibodies (aOX40/aCTLA-4) failed to induce tumor regression of larger, more established tumors. The gene discussed is CTLA4; the disease is neoplasm.