Prostate cancer and prostatitis are both significant health concerns. A large number of studies have established that the occurrence of the two is closely related. However, the most common prostatitis, type III chronic prostatitis/chronic pelvic pain syndromes (CP/CPPS), is reported to not correlate with the occurrence of prostate cancer. Although the etiology of CP/CPPS is unknown, it may be related to the autoimmune mechanism favored by most studies. Manipulating the immune system and targeting tumor microenvironment are promising new methods for the treatment of prostate cancer. Therefore, this review focuses on the immune cells and cytokines of CP/CPPS and prostate cancer from the perspective of biological immunology and immune microenvironment. We discuss T-regulatory (Treg) and T helper 17 (Th17) cells dysfunction, the abnormal regulation of T helper 1(Th1) and T helper 2 (Th2) cells, macrophages, and their related cytokines as key activators in CP/CPPS. In addition, we discuss the roles of Treg and Th17 cells, Th1 and Th2 cells, and related cytokines in modulating prostate cancer progression. This review highlights the concept that immune cells and cytokines provide a research strategy for the etiology of CP/CPPS and offer potentially promising targets for the treatment of prostate cancer.