Tumors are a major cause of human mortality worldwide, and the rapid development of nanomaterials (NMs) for tumor therapy and drug delivery has provided new treatment methods. However, NMs’ high immunogenicity, short circulation time, and low specificity limit their application in tumor therapy. In recent years, bionanomaterials using cell membranes have emerged to overcome the shortcomings of monomeric NMs. Cell membrane-encapsulated NMs extracted from multiple cells not only retain the physicochemical properties of NMs but also inherit the biological functions of the source cells, aiding in drug delivery. The combination of the cell membrane and drug-loading NMs offers an efficient and targeted drug delivery system tailored to the tumor microenvironment. The research and application of this method have been widely carried out in the academic field of tumor diagnosis and treatment. This review presents the recent research progress of cell membrane-coated NMs as drug carriers in tumor therapy, including cell membrane extraction methods, encapsulation strategies, and the applications of cell membrane-encapsulated NMs in tumor therapy. We believe that biomimetic nanomaterials will be a promising and novel anticancer strategy in the future, and their wide application will certainly bring vitality to the field of tumor diagnosis and treatment. The combination of membrane and drug-loading nanomaterials embodies a highly efficient and target drug delivery system tailored to the tumor microenvironment, which broadens a new path of drug delivery for future cancer treatment. Meanwhile, it is also a perfect combination and application of biomedical nanomaterials, which is of great significance.