The immigration regulations and policies in the US are administered by the US Department of Homeland Security. There are three major agencies under Department of Homeland Security charged with administering and enforcing US immigration regulations:
Immigration and Customs Enforcement (ICE): The primary functions of ICE are immigration and customs investigations, customs air and marine interdiction, immigration and customs intelligence, detention, and removal.
Customs and Border Protection (CBP): As a single unified border agency, CBP is charged with border patrolling, customs service, and immigration inspection at the ports of entry (land borders, airports, and harbors). When you enter the US, your first contact will be with an agent from this agency.
US Citizenship and Immigration Services (USCIS): Most adjudication of immigrant and non-immigrant benefits will be done by USCIS either at the local USCIS Office or by mailing applications to a USCIS Service Center. As a scholar/faculty you might be filing an application for change of status, for Adjustment of Status or for benefits for a spouse. These are all examples of applications adjudicated by USCIS.