Pépé began his senior club career with Poitiers in the Championnat de France Amateur 2. He signed for Angers in 2013, aged 18, and spent a season on loan at Orléans in 2015. He signed for Lille in 2017, and was named to the UNFP Ligue 1 Team of the Year in the 2018–19 season. That summer, Pépé joined Arsenal for a club-record fee of £72 million, and won the FA Cup in his debut season.