DB used to be one of the biggest (top 10 or so) equity underwriters in the world.
That means, if you had a private company and wanted to IPO, you could hire them. They also buy and sell securities for big investors (hedge funds, pension funds, universities, high net worth, etc.). That is a very lucrative business, and they bailed in July 2019 (or announced that they would).
They are still in the Fixed Income business (bonds), but much less so.
They basically waved the white flag on the most lucrative banking business because they fucked their balance sheet up so badly and needed to cut long term costs.