Cancer-related fatigue (CRF) is one of the most prevalent and debilitating symptoms experienced by individuals undergoing or recovering from cancer treatment. Exercise oncology has emerged as a rapidly expanding field, offering strong evidence that structured physical activity can effectively reduce CRF and improve physical fitness across diverse cancer populations. This progress has important clinical implications, as identifying the most effective exercise strategies can directly inform personalized supportive care. Research consistently shows that aerobic, resistance, high-intensity interval training (HIIT), multimodal programs, mind-body interventions, and technology-supported exercise reduce CRF and improve physical performance. Studies indicate that supervised and combined modality programs seem to be the most effective. Exercise is safe and practical at all stages of treatment, including during chemotherapy, radiotherapy, hormonal therapy, immunotherapy, and in advanced disease. Existing gaps encompass the personalization of exercise intensity, understanding mechanisms, and studies in underrepresented groups. Physical activity should be viewed as an essential aspect of supportive cancer treatment