Recombinant IL-2 (aldesleukin) is a potent T cell proliferation and differentiation factor and is an approved immunotherapy for advanced melanoma and renal cell carcinoma. Single agent efficacy of ODC-IL2 in subcutaneous syngeneic tumor models with diverse TME composition is shown. In conclusion, we have demonstrated proof of concept of the On Demand Cytokine platform and its potential to deliver safe and effective immunotherapies.