Together, these data suggest that the combination therapy consisting of CAN-2409 + prodrug treatment and anti–CTLA-4 antibody therapy improved tumor control beyond that observed with CAN-2409 + prodrug alone and CTLA-4 alone, which could be explained by simultaneously enhancing the CD8+ T-cell response and impeding accumulation of Tregs. Here, CTLA4 is linked to neoplasm.