Onconephrology, an emerging field in modern medicine, is gaining importance due to its intricate challenges derived from the mixing field of tumorous and renal diseases. The growing incidence of tumors in transplant patients requires preventive strategies and accurate monitoring. Pre-transplant screening is crucial, focusing on subjects with oncological history. Post-transplant follow-up must be personalized, tailoring screenings for patients with cancer history. Immunosuppressive therapy, although essential to prevent organ rejection, represents a delicate balance between controlling the immune response and cancer risk management. Immune checkpoint inhibitors emerge as a fascinating potential for cancer therapy, but their use in transplant patients requires caution and further research to carefully evaluate their safety and effectiveness, balancing potential benefits with actual risk of rejection. In summary, onconephrology is a growing field that requires an interdisciplinary approach and constant research, aimed at successfully addressing the complex challenges associated with oncological diseases in renal and transplant patients.Copyright by Società Italiana di Nefrologia SIN, Rome, Italy.