IL-23 is one of the most intriguing cytokine for its many immunological functions, which are the basis of its important role in host defense but also of its possible contribution to the pathogenesis of several diseases. The literature and patents about IL-23 pathway and their targeting in therapeutic potential applications. Findings published within the last 5 years receive particular attention. An overview of the emerging role of IL-23 in physiological and pathological conditions and a review of the different approaches (IL-23 pathway-based) currently used for autoimmune diseases and cancer therapies and the results obtained both in preclinical models and in clinical trials. Inhibition/targeting of IL-23 may be a good and novel therapeutic strategy, especially in the treatment of diseases like psoriasis, for which current treatments show more pronounced side effects than those of IL-23-blocking and employed as part of specific patient-tailored therapies in inflammatory bowel diseases.