Doug McMillon, president and CEO of Walmart, will be the new chairman of the Business Roundtable, taking over from JPMorgan Chase & Co. CEO Jamie Dimon on the first of January 2020.

McMillon will serve a two-year term, the organization said Thursday. He joined the group, which serves as an influential association of CEOs at some of the country’s largest companies, in 2014.

“In the coming months, there will be extensive conversations about America’s future and the role business plays in shaping it,” the executive said in a release. “As chairman, I commit to keeping Business Roundtable CEOs at the forefront of constructive public policy debates as we pursue an agenda of greater growth and opportunity for all Americans.”

Walmart was No. 1 on this year’s Fortune 500, with $514.4 billion in revenue and $6.7 billion in profits.

McMillon’s appointment comes at a critical time for the Roundtable. In August, the group announced a major shift—marked with a Fortune cover story—in its stated purpose, from serving the shareholder first to a more holistic vision that includes pointed references to serving customers, supporting local communities, and prioritizing diversity and inclusion.

That change is “an acknowledgment that business can do more to help the average American,” current chairman Dimon told Fortune.

It also comes at a crucial time for McMillon. The executive has faced pressure to speak out on gun control after two mass shootings at Walmart locations in El Paso, Texas and Southaven, Mississippi this summer. In September, McMillon said the company would no longer sell certain kinds of ammunition, and would ask customers to not openly carry firearms in its stores.