Following intense research efforts, modulation of the immune system has finally proved to be a viable approach for treating malignant disease. Recently, chimeric antigen receptor redirected T cells have achieved promising outcomes in patients with B-cell malignancies and they are currently also being investigated in other haematological malignancies, solid tumours and viral infections. Compared with traditional biopharmaceuticals, the properties of genetically modified chimeric antigen receptor redirected T-cell therapies differ in many aspects, thereby posing challenges in terms of post-authorisation data collection and data analysis. We believe that the network of population-based Nordic healthcare databases has some characteristics that can help provide important data on these new types of advanced products. In particular, the possibility of very long follow-up periods with a limited loss to follow-up is an important strength. Given the limited source population and slow access to data, a Nordic chimeric antigen receptor redirected T-cell monitoring project should be seen as complementary to other surveillance initiatives.