For the first time since the first televised debate between John F. Kennedy and Richard Nixon in 1960, there will be no live audience at CNN's studio in Atlanta.

The candidates' microphones will be muted unless it is their turn to speak. They will have two minutes to respond to questions and one minute for rebuttals, and there will be a red flashing light to indicate to them their time is about to expire.

The 90-minute program will have two commercial breaks, but Trump and Biden won’t be able to consult with their teams during them. No props or note cards are allowed on stage.

Here's what experts said about the new rules, and how they may help or hurt each candidate.

Several possible vice presidential picks for Trump are in Atlanta for the debate.

Sens. Marco Rubio, R-Fla., Tim Scott, R-S.C., and J.D. Vance, R-Ohio, Rep. Elise Stefanik, R-N.Y., and former Housing and Urban Development Secretary Ben Carson were seen in a picture posted to X by Stefanik.

Trump has repeatedly teased an announcement of who will join him in the 2024 ticket, but he has yet to make a final decision.

Voters across Wisconsin, Michigan, Georgia and Pennsylvania spoke with ABC News about their unhappiness with both candidates and what they're looking to hear from them during the debate.

"I'd like to see what they're going to do for small businesses in this country," said Scranton resident Jennifer Merceau, whose husband owns a masonry company.

Janee Johnson, who works at Toast 'N Jams in Muskegon, Michigan, said the focus should be on doing the "right things for America."

Michael Kordecki, the owner of that restaurant, wishes he could tell the candidates to "be more positive about America, about our future, and about what we can do with or without new people coming into the country."

Read more about these voters here.

With 131 days until Election Day, this faceoff is occurring months ahead of the usual fall timeline.

"The combination of having so many people with doubts about both candidates, coupled with the first debate occurring before either convention, heightens its potential importance," Republican political strategist Whit Ayres told ABC News.

Veteran Democratic strategist James Carville told ABC News: "People's attitudes are very fixed and voters tend to be pretty entrenched. The person that 'wins' ... in this debate is going to be the one that provides voters with some new information."

-ABC News' Isabella Murray and Tommy Barone

Heading into tonight's event, Biden and Trump are locked in a close contest. 538's presidential election forecast rates the race as a dead heat, with both Biden and Trump having about a 1 in 2 shot of winning the election. This falls in line with our national polling average, which has the two candidates just about tied at 41%, with Kennedy polling at 9%.

But as readers know, U.S. presidential elections aren't decided by the national popular vote. Instead, they're decided by the Electoral College, where the results in individual states determine who wins each state's electoral votes, with a majority of 270 out of 538 in total necessary to claim victory. Currently, the forecast shows an extremely tight race in each of the most pivotal states.

For instance, Biden's path to victory may rest primarily on winning the Frost Belt battlegrounds of Michigan, Pennsylvania and Wisconsin that he carried in 2020. While the forecast shows him with small leads in each of those states, Biden's advantage is well inside the range of potential outcomes, meaning Trump could easily carry them once we get to November. Meanwhile, Trump holds a narrow edge in the Sun Belt swing states of Arizona, Georgia, Nevada and North Carolina, but similarly his leads are far from secure.

Still, with nearly four months to go until Election Day, there's a great deal of uncertainty around where public opinion will stand when voters cast their ballots. 538's forecast utilizes a combination of polling information and campaign fundamentals, such as the economic situation and each state's partisan leanings. Together, those indicators show a toss-up race that could go in either direction.

Now, tonight's debate could move the contest: Historically, the margin in presidential races has shifted by an average of about 2 points in the two weeks following the first general election debate in cycles dating back to 1976. In what could be bad news for Biden, that movement has more often than not gone against the incumbent president or party. Yet we're still sailing in uncharted waters. After all, this election involves both a sitting and former president, an unprecedented matchup in modern times. The debate is history-making, too: It's nearly three months earlier than any past general election face-off.

-538's Geoffrey Skelley