The article reviews the evolution of oncolytic immunotherapy (OI) since the FDA approved talimogene laherparepvec for melanoma in 2015. It discusses the development of next-generation herpes simplex virus-based OIs, focusing on genetic modifications for safety, tumor-selective replication, and immune stimulation. The review also covers clinical evidence supporting OIs in overcoming resistance to immune checkpoint blockade and explores combination therapies to enhance OI efficacy.