Several things about tonight are new and different.
For the first time, the President will be flanked by two women: Vice President Kamala Harris and House Speaker Nancy Pelosi.
It will NOT be a full house. Tickets for the socially-distanced speech are very limited, and seats will be spaced out for safety due to the pandemic. All will wear masks, and Biden will remove his mask to give the speech.
Presidents cannot give "State of the Union" speeches until they have served for a year in office. This is a Presidential Address at the invitation of the House Speaker.
There will be two responses to the address: Tim Scott of South Carolina will give the Republican response and "Rep. Jamaal Bowman (D, N.Y.), speaking on behalf of the left-wing Working Families Party, said he plans to deliver a speech to cue the president in on what progressives want to see next out of the administration." per The Philadelphia Enquirer.