New Medicare cards are on the way

Changes are coming to your Medicare card. By April 2019, your card will be replaced with one that no longer shows your Social Security number. Instead, your card will have a new Medicare Beneficiary Identifier (MBI) that will be used for billing and for checking your eligibility and claim status.

https://www.consumer.ftc.gov/blog/2017/05/new-medicare-cards-are-way