German international defender Koch joined Leeds United from SC Freiburg in August 2020 following the club's promotion to the Premier League.
He started his career with Eintracht Trier, before moving to FC Kaiserslautern and then Freiburg.
Upon signing, Koch penned a four-year deal at Elland Road, running until the summer of 2024.
He made his Leeds United debut against Liverpool at Anfield on 12 September 2020.
The 25-year-old was part of the Germany squad that was knocked out of Euro 2020 by England.