For those who didn’t know (like me):

He shall from time to time give to the Congress Information of the State of the Union, and recommend to their Consideration such Measures as he shall judge necessary and expedient; he may, on extraordinary Occasions, convene both Houses, or either of them

If Johnson doesn’t gavel in the House, Biden can force them to do so. Though I don’t think it likely for Johnson to not have a session, because their plans hinge on ignoring legitimate electors under the guise of “irregularities”.