From the Document: "The Islamic State (IS, also known as ISIL, ISIS, or the Arabic acronym 'Da'esh') is a transnational Sunni Islamist insurgent and terrorist group. At its 2015 height, the group controlled large areas of Iraq and Syria, including some cities, from which it launched attacks in the region and beyond. While the group no longer controls territory outright in Syria and Iraq, U.S. military officials warn that it has maintained a low-level insurgency and has worked to expand its global presence via a burgeoning number of affiliate groups. The 2021 Annual Threat Assessment of the U.S. Intelligence Community (IC) warned that the Islamic State and sometimes rival Al Qaeda 'have shown great resiliency' and together remain the 'the greatest Sunni terrorist threats to U.S. interests overseas.'"
CRS In Focus, IF10328
Congressional Research Service: https://crsreports.congress.gov/