The immune system is composed by a myriad of cells that have different roles in protecting the body against infections and cancer. In recent years, an increase understanding of the immune system has brought to the development of new cancer therapies that take advantage of the ability of the immune system to kill tumor cells. These immunotherapies have been successful in several tumor types, but not in prostate cancer. We believe that one reason why immunotherapy is not as effective in prostate cancer is that some immune-regulatory mechanisms are in place in the prostate that are currently not known. Here, we will analyze a population of immune cells, called innate lymphoid cells, that have been shown to have great immunomodulatory potential. By increasing our understanding of innate lymphoid cells in the prostate, we believe we will be able to design new and more effective immunotherapies for prostate cancer.