Poku has been hired by Besiktas on a temporary basis, with an option to buy. The deal includes a possible transfer fee of 20 million euros, while 3 million euros will be paid for the loan itself. The option to buy could become a requirement under certain conditions. VoetbalPrimeur reports that Fiorentina and Premier League clubs were also interested in Poku, but ultimately missed out on his services. Poku played 45 games for Bayer Leverkusen, scoring five goals and providing eight assists. He previously played for AZ, where he made 79 appearances and provided 14 assists.