Cancers remain a devastating and challenging disease to treat partially due to a population of cells termed cancer stem cells (CSCs). CSCs are resistant to conventional cancer treatments and are capable of re-establishing disease. While surgery, chemotherapy, and radiotherapy are routine cancer treatments, additional strategies are required to eliminate CSCs. Innovative approaches to target CSCs using immunotherapy are emerging, and studies of their efficacy are underway. However, the tumour-immune interactions are complex, and numerous mechanisms remain unclear. Preclinical investigations of adoptive T cell therapies, immune checkpoint inhibitors, dendritic cell-based vaccines, oncolytic viruses, and combination therapies targeting CSCs in several solid and haematological cancers are increasing. Although limited, there are promising results with immunotherapies against CSCs that facilitate more research in this growing field.