Medicare and VA benefits are separate systems that don't coordinate, so you choose which to use for each service: use your VA card at VA facilities, and use your Medicare card at Medicare-approved civilian providers, with Medicare covering care outside the VA system and VA covering care within its facilities. Having both provides flexibility, allowing you to see a VA doctor for primary care and a non-VA specialist with Medicare, but the VA won't pay Medicare costs, and Medicare won't pay VA costs.