The Islamic State of Iraq and al-Sham (ISIS)’s affiliate in the Afghanistan-Pakistan region is effective, operational, and positioned to expand. The affiliate, Wilayat Khorasan, controls populated areas in Afghanistan’s eastern Nangarhar Province and has launched attacks on Jalalabad and Kabul. Afghanistan’s security is deteriorating and will likely worsen. Taliban infighting has intensified after the official announcement in July 2015 that Mullah Omar, the movement’s founder, had died several years ago. These violent conditions will likely facilitate Wilayat Khorasan’s recruitment, attacks, and territorial expansion. Afghanistan’s precarious unity government has not maintained effective security as international forces have drawn down. Wilayat Khorasan’s growth gives ISIS additional strategic resiliency outside of Iraq and Syria and will intensify the global competition between ISIS and al-Qaeda (AQ), which is also present in the area. The United States and its NATO allies must respond more aggressively to this threat.