This review will provide an overview of cytokine and cytokine-based immunotherapy and focus on recent developments in new-era oncological treatment, including several combinations of both conventional cancer therapy and novel immunotherapy with cytokine, and their applications in clinical research. There are five main parts, (1) The technology of cytokine immunotherapy, (2) The function of cytokine immunotherapy and defects of cytokine as a monotherapy, (3) The specific cancers that are targeted by synergistic cytokine immunotherapy, and (4) Prospects of cytokine in immunotherapy.