Abstract
After decades of intense effort, therapeutics that leverage the immune system to fight cancer have now been conclusively demonstrated to be effective. Immuno-oncology has arrived and will play a key role in the treatment of cancer for the foreseeable future. However, the search for novel methods to improve immune responses to cancer continues unabated. Toward this end, small molecules that can either reduce immune suppression in the tumor milieu or enhance activation of cytotoxic lymphocyte responses to the tumor are actively being pursued. Such novel treatment strategies might be used as monotherapies or combined with other cancer therapies to increase and broaden their efficacy. In this article, we provide an overview of small molecule immunotherapeutic approaches for the treatment of cancer. Over the next decade and beyond, these approaches could further enhance our ability to harness the immune system to combat cancer and thus become additional weapons in the oncologist's armory.