Combination therapy strategy of tumor immune checkpoint inhibitor and its clinical application

The implementation of immune checkpoint inhibitions (ICIs) has improved the prognosis of multiple cancers. Anti-programmed cell death 1(PD-1)/anti-programmed cell death 1 ligand 1 (PD-L1) and anti-CTLA-4 monotherapy showed the limited efficacy in clinical studies and there are unmet needs for the development of new strategy of immunotherapy. Currently, combination therapy strategies including combination of different ICIs, chemotherapy, or anti-angiogenesis agents have increased the response rate of ICIs in multiple cancers. The development of the inhibitors of novel immune checkpoint such as lymphocyte activation gene-3(LAG-3), T cell immunoglobulin mucin-3(TIM-3), and T cell immunoglobulin and ITIM domain(TIGIT) will be expected for further improving the survival of refractory cancer patients or patients who are resistant to present ICIs.