This Year Nobel Prize in Medicine is awarded to two scientists: James P. Allison of the United States and Tasuku Honjo of Japan, who contributed to the description of biological mechanisms that control the immune response. Modulation of these mechanisms lead to the availability of immune checkpoint inhibitors, a new class of therapeutic agents that have entered medical practice in oncology at an accelerated pace. Not only is this a great hope for patients, some of them affected with life-threatening neoplastic diseases; it also lead to fully revisit therapeutic strategies in oncology, complementing the administration of agents or combinations with direct cytotoxic activity, with the exploitation of the host – tumor interactions. Immune checkpoint inhibitors also represent a long-awaited commercial success for medicinal products that “boost” the ability of the patient immune system to control cancer progression. The field of immunotherapy is now blooming with the development of many other forms of treatments, including adoptive transfer of immune effector cells.