Nintendo is the latest of the big gaming companies to bow out of E3 this year. The company said this year's show "didn't fit into our plans," so they've opted out of having a presence on the show floor. We might get a Nintendo Direct event in June, but it won't be connected with the expo.
Microsoft hasn't confirmed that it would be part of this year's show. But Microsoft Gaming CEO Phil Spencer recently hinted that the company plans its annual showcase in Los Angeles this summer around the same time as E3 (which runs between June 13 and 16). Meanwhile, Sony hasn't had a presence since 2018. And there are rumours it plans to host a major showcase ahead of E3.