Tumor immunology deals with the natural or therapy-induced recognition of cancers, as well as with the intricate interplay between oncogenesis, inflammation and immunosurveillance. We now create a new, high-profile journal, OncoImmunology, that specifically deals with tumor immunology. Recent progress has allowed for the first clinical demonstration (and FDA approval) of anticancer immunotherapies. There is also an ever growing suspicion that - unexpectedly - many of the currently used chemotherapeutic agents depend in their efficacy on the active contribution of immune effectors. To use a drastic metaphor, oncologists who applied successful chemotherapeutic (or radiotherapeutic) regimens have taken advantage of the immune system's capacity to recognize tumor-specific or tumor-associated antigens and to control cancer (stem) cell growth, without being aware of the invisible helping hands. As a result, immunological biomarkers are becoming ever more important to determine the prognosis of cancers and to predict the efficacy of chemotherapies. There is also a strong rationale in favor of combining conventional anticancer therapies with immunotherapies.