4-1BB agonists, soluble 4-1BB ligand and other agents that provide systemic co-stimulation can promote anti-tumor immunity but are not cell intrinsic and can also trigger inflammation.30 The Fas-4-1BB IFP selectively targets co-stimulation to tumor-specific T cells, resulting in intratumoral T cells expressing more anti-apoptotic molecules and IL-2, together promoting T cell survival/proliferation and antitumor efficacy. The gene discussed is FAS; the disease is neoplasm.