Trump and Biden are facing off very early in CNN's presidential debate. Here's why

U.S.President Joe Biden and former U.S. president Donald Trumpwill debate at 9 p.m. ET on Thursday evening on CNN.

Here's a brief look at why it's making headlines ahead of the actual event.

Who is taking part?

Biden, the Democrat incumbent, and Trump, his Republican rival. Both men are the presumptive nominees of their respective parties.

What about Robert F. Kennedy Jr.?

He didn't make the cut, as per CNN's criteria.

Isn't this a bit early?

With the U.S. election set for Nov. 5, Thursday's debate is the earliestin modern U.S. history a timing made possible, in part,because it'sso clear so early whothe presumptive nominees are.

The Commission on Presidential Debates, a non-partisan group that has organized such events for more than three decades,was not involved in the planning of the CNN debate.

A second debate between Biden and Trump is scheduled to take place on Sept. 10. It will be hosted by ABC. The commission is not involved in that event either.

In May, Biden said he would not participate in commission-organized debates, and hepublicly challenged Trump to a debate. The CNN and ABC debates were then announced soon afterward, with Trump agreeing to participate in both.

Where is it being held?

At the CNN studios in Atlanta.

What's the format?

CNN has said the debate will last 90 minutesand will be held without an audience.

The participants' microphones will be muted when they are not slated to be talking.

Who's moderating?

Veteran journalists Dana Bash and Jake Tapper, both of whom work for CNN.

The same duo have moderated debates together in the past, including a Januaryeventin Des Moines, Iowa,between then-Republican presidential contendersRon DeSantis and Nikki Haley.(Trump didn'tparticipate.)

Days ahead of this week'sdebate, Trump-allied voices areaccusing Bash and Tapper ofbias against the former president though the network has defended the moderators.

Both Tapper and Bash criticizeda September 2020 presidentialdebate between Biden and Trump, as didother outlets and journalistsin the U.S. and elsewhere, for its chaotic and bitter character, and then-incumbent Trump's refusalto condemn white supremacists. Bash's memorabledescription of the debate, after the fact,drew attention.

It wasn't the first time the two werecritical ofTrump.

He and his campaign are nonethelessputting a focus on these two journalists as the debate draws nearer.

At a rally in Wisconsinearlier this month, Trump made reference to facing off against "three people" in the coming debate,apparently includingthe CNN moderators in his count.

What's at stake for Biden?

Thursday's debate gives Biden a chance to make his case for re-election.

At81, Biden is already the oldest president in U.S. history. Another full term in office wouldsee him serving in that role into his mid-80s.

His age has been a focus of media attention throughout his presidential term to date. It has also been at the centre of attacks from Trump and some Republicans.During the debate, Biden will be able toshow his leadership capabilities on live TV.

Biden and 78-year-old Trump who'sfaced his own questions about his mental fitnessare together the two oldest nominees to seek the Oval Office.Thursday's debate could be relevant for those with concerns about the candidates' ages.

"It's an incredible test of their cognitive competence," Patrick Stewart, a political science professor at the University of Arkansas, told Reuters. "This is our chance to see how much they've declined, or if they've declined."

But being the sitting president, Biden may expect to face questions on hot-button issues the country is facing right now.

Brian Hughes, a senior adviser to the Trump campaign, told Reuters thatinflation, immigration and "a world on fire" with major wars in Ukraine and Gaza are key issues the campaign wants to make Biden speak to.

What about for Trump?

Trump has been navigating legal challenges since leaving office, including being convicted in a hush-money trial. And he also faces three other trials including his alleged mishandling of classified documents, and alleged efforts to overturn the 2020 electionresults to come.

During the debate, Trump may speak to voters about thesecases. He could also beconfronted about them.

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Yet aside from any issues raised during the debate, Trump will have to perform on a stage he has not occupied in some time, having skipped such face-offs against Republican rivals (like the Iowa debate).

Trump signalled last summer that he would not take partin thedebates held during the Republican primaries, as voters were familiarwith him personally and with his record.

Alan Schroeder, a professor emeritus of journalism at Northeastern University, sees some risk for Trump, amid a looser debate format.

"He's done so many TV events of different types that he sort of thinks he can wing it," Schroeder, who is an expert on presidential debates,told Reuters.

"But debating is a very specific thing. It doesn't really pay to just show up."