He was arrested on a German warrant, and the purpose of his arrest is to eventually extradite him to Germany. But Israel has been pressing Poland not to do that.
Even if Poland extradites him, Germany will do no more than declare him persona-non-grata, bar him from the country, and ‘deport’ him to Israel.
Its not important as to what happens to him. At this stage, whats important is the worldwide perception that Israel has taken a free ride for way too long, and needs to be reined in. Change is coming slowly and steadily.