The present invention relates to the treatment of cancer using combination therapy comprising a dual modulator of Insulin Receptor Substrate (IRS) and signal transducer and activator of transcription 3 (Stat3), in combination with an antibody against programmed cell death 1 (PD-1) protein, an anti-programmed cell death protein 1 ligand (PD-L1) antibody, or a combination thereof. The combination can be used to re-sensitize a tumor that may develop or has developed resistance to the anti-PD-1 and/or anti-PD-L1 antibody, by enhancing response of the tumor to the anti-PD-1 and/or anti-PD-L1 antibody, converting non- responding tumors to responders and/or blocking tumor progression.
