AbstractCancer immunotherapy is a groundbreaking medical revolution and a paradigm shift from traditional cancer treatments, harnessing the power of the immune system to target and destroy cancer cells. In recent years, DNA nanostructures have emerged as prominent players in cancer immunotherapy, exhibiting immense potential due to their controllable structure, surface addressability, and biocompatibility. This review provides an overview of the various applications of DNA nanostructures, including scaffolded DNA, DNA hydrogels, tetrahedral DNA nanostructures, DNA origami, spherical nucleic acids, and other DNA‐based nanostructures in cancer immunotherapy. These applications explore their roles in vaccine development, immune checkpoint blockade therapies, adoptive cellular therapies, and immune‐combination therapies. Through rational design and optimization, DNA nanostructures significantly bolster the immunogenicity of the tumor microenvironment by facilitating antigen presentation, T‐cell activation, tumor infiltration, and precise immune‐mediated tumor killing. The integration of DNA nanostructures with cancer therapies ushers in a new era of cancer immunotherapy, offering renewed hope and strength in the battle against this formidable foe of human health.