Dendritic cells (DCs) play a crucial role in maintaining the immune system. DC-based immunotherapy is known as the “cancer vaccine” for advanced cancers and to prevent recurrence. Though DC-based cancer immunotherapy has been suggested as a potential treatment for various kinds of malignancies, its clinical efficacies in many human trials are still insufficient. To identify the causes of these low efficacies, many investigators have focused on the numbers of administered DCs, how they are activated, which type is best, and so on. This review focuses primarily on patents analysis of recently developed DC-based cancer immunotherapies. We also analyze the critical factors of DC-based cancer immunotherapy to best optimize the development of these novel technologies.