Methods of treating a subject for a cancer comprising neoplastic cells expressing the CD40 cell surface antigen are provided. The methods comprise combination therapy with interleukin-2 (IL-2) or biologically active variant thereof and at least one antagonist anti-CD40 antibody or antigen-binding fragment thereof. In some embodiments, these two therapeutic agents are concurrently administered as two separate pharmaceutical compositions, one containing IL-2 or biologically active variant thereof, which is administered according to a constant IL-2 dosing regimen or a two-level IL-2 dosing regimen, the other containing the antagonist anti-CD40 antibody or suitable antigen binding fragment thereof, which is administered according to a weekly dosing regimen, or alternatively is dosed once every two, three, or four weeks.; Administering of these two agents together potentiates their effectiveness in promoting a positive therapeutic response. The methods find use in treating CD40-expressing cancers, including B-cell related cancers and solid tumors.