Sen. Bernie Sanders told "The Late Show with Stephen Colbert" in an interview airing Wednesday night that he's in talks with his former 2020 rival Joe Biden on working together to beat President Trump. But he stopped short of endorsing him.

Why it matters: Now that Sanders has suspended his presidential campaign, Biden is the presumptive Democratic nominee. Some of Sanders' loyal supporters have said they don't trust Biden and may not vote for him. "I hope to be able to work with Joe to move him in a more progressive direction," Sanders told CBS host Stephen Colbert. Biden earlier Wednesday praised the progressive movement built by Sanders.

Go deeper: Sanders: "While this campaign is coming to an end, our movement is not"

Editor's note: This article has been updated with more details from the interview and more context.