Short answer: Gegenpressing is counter-pressing immediately after losing the ball, Jürgen Klopp's signature style.
Gegenpressing (German for 'counter-pressing') means swarming the opponent within 5-6 seconds of losing possession, trying to win the ball back high up the pitch. Klopp's Dortmund (2010-2015) and Liverpool (2015-2024) defined the style. Modern Premier League is largely built on it.