Methadone and Suboxone treatments are vastly different, but patients can switch from a methadone treatment program to a Suboxone program.
Methadone itself is an opioid that binds to receptors in the brain the same way that heroin or other pain medications do. Because methadone is a pure opioid agonist (binds to the receptors just like heroin or oxycodone) it requires a very structured program where patients often come to the clinic and get their medication, and then take the pills in front of a person working at the facility. In the United States, methadone can also be used as a pain medication.
Alternatively, Bupernorphine (one of the medicines in Suboxone) is a partial agonist, meaning that it binds to the opioid receptors, but in a different manner. Suboxone also contains naloxone, which is a medication that prevents you from getting a "high" while on the medicine. These two medications combined allow Suboxone to treat both your cravings and withdrawal symptoms. This also allows the medication to be used by the patient in their home and doesn't require daily visits to receive the medication.