Parkinson's disease (PD) is a neurological condition, which affects the brain. PD gets worse over time, but how quickly it progresses varies a lot from person to person. Some symptoms of PD are tremors, stiffness, and slowness of movement. This study will assess how effective Foslevodopa/Foscarbidopa is in treating adult participants with advanced Parkinson Disease under routine clinical practice in Belgium. Foslevodopa/Foscarbidopa is an approved drug for the treatment of Parkinson's Disease. Approximately 120 adult participants who are prescribed Foslevodopa/Foscarbidopa by their doctors will be enrolled at 15 sites across Belgium. Participants will receive Foslevodopa/Foscarbidopa subcutaneous infusion as prescribed by their physician. Participants will be followed for up to 18 months. There is expected to be no additional burden for participants in this trial. Participants will attend regular visits during the study at a hospital or clinic according to their routine clinical practice.