Who Controls the Senate in a 50-50 Tie?
Article I, Section 3 of the Constitution specifies that The Vice President is the President of the Senate. The Vice President has no vote unless to break a tie in some matter before the Senate.
Therefore, if there is a 50-50 party split in the Senate, the Vice-President's vote will give the majority to his or her party. That is the situation we currently have in the Senate. With a Democratic vice president, that party controls the chamber.
In the 2022 midterms, 34 Senate seats are to be contested. 20 are held by Republicans and 14 by Democrats. A net gain of one seat in those elections would return control to the GOP in January, 2023.