Its horrible techniques of torturing and slaughtering its enemies (which is pretty much everyone else) is considered extreme even for other terrorists and gave it during its prime days a vile reputation.

Recently 400 ISIS operatives with European citizenship, were chosen to return to Europe on a secret mission. The operation started three and a half years ago (mid 2019) with the goal to return to Europe without their real documents and to lead new terror cells on the continent. They were chosen due to their loyalty to ISIS, leadership, achievements in battlefield, and radical perspectives.

ISIS infrastructure and resources are based on criminal activities, so that apart from the imminent threat of terror attacks, we can expect a profound rise of criminal activity on the streets of Europe.

Source: GFATF - Global War Against Terrorism Funding