The main purpose of the trial is to evaluate the safety and potential side effects of cell therapy vididencel in Chronic Myeloid Leukemia (CML) participants with measurable residual disease (MRD) unable to stop treatment with tyrosine kinase inhibitor (TKI). Patients may not receive any direct medical benefit from participating. Participants in the study should have been treated with TKI for at least 24 months prior to enrolment. This TKI must be of the same type throughout the 24 months. Participation in the active period of the study will take about 5 months after which patients will be followed with regular checks for a total of 3 years from the study start. The cell therapy is administered as 2 low-volume intradermal injections.The first 4 treatments will be performed once every two weeks over a period of 6 weeks. Further treatments are given 14 and 18 weeks after the start of participation as 1 low-volume intradermal injection.The belief is that addition of the study treatment (vididencel) to tyrosine kinase inhibitor therapy may potentially strengthen the immune defence so that enough leukemic cells are killed that the TKI treatment can eventually be decreased in dose or even stopped permanently, without the CML progressing again.