Answer
Holtby has signed for three Bundesliga clubs in his career: Hamburg, Schalke, and Wolfsburg. He started his career at Hamburg in 2007 and made his Bundesliga debut in 2009. He played for Hamburg until 2012, when he moved to Schalke. He played for Schalke for two seasons before moving to Wolfsburg in 2014. He has played for Wolfsburg for three seasons and is still with the club today.