The understanding of the immune system and the discovery of the proteins and processes involved in its regulation have enabled the emergence of new approaches against cancer. The development of antibodies (immune checkpoint inhibitors) able of blocking interactions that suppress the activation of T cells or their effector actions against cancer cells has modified the prognosis of several cancer forms. Bispecific antibodies as well as cellular immunotherapies (CARs/TILs) are new immunotherapy approaches that have already shown their effectiveness in certain onco-haematological diseases. Unfortunately, only a fraction of treated patients derives benefit from these treatments. The future challenge will be to understand the resistance mechanisms to immunotherapies so that treatment may be personalized for each patient.