Kevin Harrington, PhD, MBBS, Institute of Cancer Research and the Royal Marsden NHS Foundation Trust, London, UK, gives us an update on oncolytic virotherapy, touching upon talimogene laherparepvec (T-VEC), the first oncolytic virus approved for the treatment of melanoma, before highlighting newer agents utilizing herpes simplex virus (HSV) with a transgene to modulate the immune response in multiple solid cancer types. This interview took place at the European Society for Medical Oncology (ESMO) 2019 congress in Barcelona, Spain.