U.S. Immigration Customs and Enforcement, better known by its acronym as ICE, is a law enforcement agency under the jurisdiction of the Department of Homeland Security. It has two main tasks: investigating and stopping national security threats and the enforcement of the nation's immigration laws. It is for the latter role that the agency is best known.
ICE was created in 2002 as part of the Homeland Security Act. It assumed roles previously belonging to the US Customs Service and the US Immigration and Naturalization Service (INS).
It is important to note that ICE does not patrol the borders and is not the agency responsible for separating families at the border. That is US Customs and Border Protection, whose law enforcement agency is the US Border Patrol.
Viewing ICE as the embodiment of President Trump's immigration policy, a movement has formed in some progressive circles that calls for the agency to be abolished.