No.

It is illegal to enroll in both a Medicare Supplement plan and a Medicare Advantage plan. If you were to enroll in both plans, neither would become your primary coverage, leading to a denial of services. This could leave you paying out-of-pocket for all your healthcare services, regardless of having both coverages.

To avoid this, it is illegal for an agent to enroll you in one plan if you are already enrolled in the other and do not have a valid way out of the plan.