Scared?

You bet.

President Trump is discussing with his advisers the possibility of sitting out the general election debates in 2020 because of his misgivings about the commission that oversees them, according to two people familiar with the discussions.

  NYT

Because he knows he can't stand up to any Democratic nominee.

Mr. Trump has told advisers that he does not trust the Commission on Presidential Debates, the nonprofit entity that sponsors the debates, the two people said.

Cue the "Fake News!" tweet.

Less of a concern for Mr. Trump than who will emerge as the Democratic nominee is which media personality will be chosen as the debate moderator, according to people in contact with him.

Because some of them might ask a question he doesn't like?

In the 2016 general election debates, Mr. Trump repeatedly complained about being at a disadvantage to Hillary Clinton, the Democratic nominee. [...] Mr. Trump and Ms. Clinton were essentially tied in the polls going into the first debate, but she received a bump after each of the three face-to-face matchups.

And with his Russia help being outed and his impeachment inevitable, he doesn't want to push his luck again.

After his performance in one of the debates was panned, Mr. Trump blamed a “defective mic” and questioned whether it was done “on purpose” to put him at a disadvantage. It turned out that a technical malfunction had indeed affected the volume of his voice during that debate, in September 2016.

That acknowledgment by the commission, however, never mollified Mr. Trump.

His 2016 debate team — led primarily at that time by Rudolph W. Giuliani, the former New York City mayor — also clashed with the commission over where to seat a group of women who had accused former President Bill Clinton of sexual assault or sexual harassment.

[...]

Former Clinton aides said they expected Mr. Trump to participate in at least one 2020 debate, despite the president’s hints that he would refuse. “Not doing any would not be strategically smart,” said Philippe Reines, a longtime Clinton adviser, who predicted that “he’ll bluff that he won’t do any with the goal of only having to do one.”

I imagine that's exactly what's going on here.

...but hey, do what you want...you will anyway.