Hot tumors like Pol ε or mismatch repair-deficient mutated cancers are likely to respond to immunotherapy, suggests Carien Creutzberg, MD, PhD, of the Leiden University Medical Center, Leiden, Netherlands, at the European Society for Medical Oncology (ESMO) 2018 Congress, in Munich, Germany. Prof. Creutzberg also brings to attention the current translational studies that explore tumor resistance mechanisms or ways to induce responsiveness to treatment.