Despite all the steps that have been made during the last decades towards the improvement of cancer treatment, for many patients the disease remains incurable. Moreover, the standard treatments such as irradiation, chemotherapy and surgery can cause a lot discomfort and unwanted side effects for patients. Currently, there are already several potential game-changing cancer immunotherapies implemented in clinical practice, and there are many more in different stages of preclinical and clinical development. While these will undoubtedly change treatment outcome for many cancer patients, unfortunately probably only a minor fraction of all cancer patients will benefit from these treatments. Therefore, further improvement of at-present used therapies, development of novel concepts as well as efforts to combine different treatments to increase overall efficacy is needed. In this thesis we aimed to improve immunotherapeutic strategies using T lymphocytes that are currently under development, by developing an improved purification method for engineered T cells and with a novel co-receptor format that can boost efficacy of anti-cancer T cells. Furthermore, we introduced a novel concept to the fast-growing field of γδT cell mediated immunotherapy, and explore strategies to further improve this new treatment.