The current scientific field of exercise interventions in breast cancer is very large. Rehabilitation focuses on restoring or improving quality of life and thus on independence and participation in life. Hence, it is important to investigate exercise interventions in the setting of rehabilitation and aftercare. It is also necessary to determine the influence of physical activity or exercise therapy on the prevention of recurrence and mortality as well as on certain side effects of the disease and its medical treatment in rehabilitation. Physical activity in rehabilitation and aftercare is feasible and safe and can be used for various purposes. Against the background of reduced fatigue, chemotherapy-induced peripheral neuropathy, cancer-related cognitive impairment, arthralgia, lymphedema, recurrence, and mortality, as well as improved quality of life, different methodological approaches and evidence can be seen. Although the overall data availability has increased, there are gaps in study documentation as well as inadequate verification of scientific approaches in rehabilitation clinics and in everyday life.