Background: Tumor recurrences or metastases remain a major hurdle in improving overall cancer survival. In anticancer therapy, some patients inevitably develop chemo-/radiotherapy resistance at some point. Cancer stem cells are the driving force of tumorigenesis, recurrences, and metastases, contributing also to the failure of some cancer treatments. Summary: Emergent evidence suggests that stem cell diseases are at the base of human cancers, and tumor progression and chemo-/radiotherapy resistance may be dependent on just a small subpopulation of cancer stem cells. Hyperthermia can be a strong cancer treatment, especially when combined with radio- or chemotherapy. It is a relatively safe therapy, may kill or weaken tumor cells, and significantly increases the effectiveness of other treatments. However, these mechanisms remain largely unknown. A literature search was performed using PubMed including cited English publications. The search was last conducted in December 2019. Search phrases included “stem cells,” “hyperthermia,” “cancer,” and “therapy.” Abstracts, letters, editorials, and expert opinions were not considered for the drafting of the study. Key Message: Our goal was to focus on and to summarize different biological features of cancer stem cells and new therapeutic approaches using hyperthermia and its potential translation to human clinical trials.