President Biden and former President Donald J. Trump have sparred for months on the campaign trail, in interviews with reporters and through paid advertisements, creating phantom likenesses of each other to thrash and tear down.

On Thursday, they will confront each other at a CNN debate in Atlanta, their first face-to-face meeting since their last onstage clash in 2020 and since Mr. Trump tried to overturn Mr. Biden’s subsequent victory at the polls. The event will give both of them a rich opportunity to deploy their attack lines and policy arguments before a national audience.

Here’s what we know about how each man will try to gain the upper hand.

Trump’s main lines of attack

Since he emerged as the presumptive Republican nominee, Mr. Trump and his campaign have focused on attacking Mr. Biden over immigration and the economy, which polls have found to be the top concerns for many voters.

Immigration

As he did during his political rise in 2016, Mr. Trump has made immigration a central focus of his campaign. He is all but guaranteed to blame Mr. Biden for a surge in illegal border crossings, calling the president’s policies overly permissive.

Mr. Trump claims that Mr. Biden’s approach to immigration has fueled violent crime — even though broader statistics do not bear that out — by citing several high-profile criminal cases that the authorities say involved immigrants in the United States illegally.

And as he stokes fear around immigration and tries to push the issue to the center of the election, Mr. Trump has falsely cast all those crossing the border as violent criminals or mentally ill. (Families with children make up about 40 percent of all migrants who have entered the United States this year.)