According to the New York Times,
President Trump and Joseph R. Biden Jr. will debate with a single moderator at each of their three matchups, the Commission on Presidential Debates announced on Wednesday, September 2.
The first debate of the general election, on Sept. 29, will be moderated by the “Fox News Sunday” anchor Chris Wallace. Mr. Wallace received high marks for his debut debate in 2016 and is known for his sharp interviewing style.
Joe Biden, 77, is the oldest major party nominee in US history, and his opponents have claimed that he is not as mentally sharp as he once was. Indeed, a June 2020 Rasmussen Reports national telephone and online survey found that 38% of likely U.S. voters think Biden is suffering from some form of dementia. This has led some to question whether the debates between Trump and Biden could be a turning point in the election campaign.
Trump currently (September 4) trails Biden in the 538 polling average by 7.4%; Biden has 50.4% in the polling average, and Trump is on 43%.
Politico reports that Trump's advisers are watching Biden closely and "studying Biden’s idiosyncrasies to identify ways to trip him up on the debate stage."