The campaign is “ensuring folks have the facts, engaging in good-faith dialogue, so we can come to some actionable items,” said Symone Sanders, a senior adviser to Mr. Biden who has helped lead the progressive outreach. “I think we will get there with a number of these groups and I think we’ll get there sooner than later.”

There is also an internal working group focused on younger voters, and Mr. Biden’s advisers said Wednesday that constituency was a top priority. And Representative Cedric Richmond of Louisiana, a national campaign co-chairman for Mr. Biden, has maintained a dialogue with his counterpart on the Sanders campaign, Representative Ro Khanna of California.

Some of Mr. Biden’s allies have also started to think about issues on which he could move further to the left. The coronavirus outbreak has sharpened attention on economic inequality and health care disparities, allies say, and while Mr. Biden has been clear that he does not support Mr. Sanders’s sweeping single-payer health care proposal, “Medicare for all,” supporters say he could make substantive overtures to progressives in other ways.

“The vice president has a very good policy right now when it comes to health care, in terms of a very strong public option,” said Representative Ruben Gallego, Democrat of Arizona and a progressive Biden supporter. “Talking to Bernie people, they would like to see a stronger universal health care package. It doesn’t necessarily have to be Medicare for all, but something that brings more people more coverage. And I think the vice president, if he moves that direction, will find a lot more support among progressives.”

Mr. Biden’s campaign did not comment on whether he was weighing changes to his health care position. But while he is not expected to embrace Medicare for all, he has adopted a number of other proposals championed by Mr. Sanders as well as by Ms. Warren, another progressive former presidential candidate.

With Mr. Sanders out of the race, one of Mr. Biden’s urgent tasks is to close his financial gap with Mr. Trump’s campaign and the Republican National Committee, which entered March with a combined $225 million cash on hand. Mr. Biden had $12 million and the Democratic National Committee had $14 million, with $6 million in unpaid bills.

Mr. Biden’s campaign and the D.N.C. are expected to have imminent conversations about setting up such a committee, said Xochitl Hinojosa, the committee’s communications director. Inside the Biden finance operation, those conversations have already begun.