This study aims to evaluate the effects of repetitive transcranial magnetic stimulation (rTMS) and aerobic exercise on cognitive function and mental health in older adults with mild cognitive impairment (MCI) and comorbid depression. Forty-five participants will be randomly assigned to one of three groups: (1) rTMS alone, (2) rTMS combined with stationary cycling exercise, or (3) sham rTMS combined with stationary cycling exercise. Participants will receive 20 intervention sessions over a 5-week period (4 sessions per week). Outcomes, including cognitive function, depressive symptoms, sleep quality, life satisfaction, self-efficacy, and gait performance, will be assessed at baseline, immediately after completion of the 5-week intervention, and at a 1-month follow-up. The findings may contribute to the development of evidence-based, non-pharmacological interventions for improving cognitive and mental health outcomes in older adults with MCI and comorbid depression.