The killing of leader Abu Bakr al-Baghdadi is a blow to Islamic State, but the group and its ideology remain dangerous with operations and links to various countries, such as Iraq.
After defeat by U.S.-backed forces, it reverted to guerrilla tactics.
According to analyst estimates, about 2,000 active combatants now operate in the country.
Sleeper cells regrouped in several provinces, carrying out attacks such as kidnappings and bombings.
The Pentagon says I.S.
Is regenerating faster in Iraq than Syria, where it's staged suicide bombings and ambushes, especially in the north, targeting U.S. forces.
The risks are compounded by the thousands of militants held in prisons, including foreigners from around the world.
Fighters still hold some ground in Syria's remote central desert.
Some extremists fleeing Syria and Iraq may be finding a safe haven in the Philippines, especially setting up cells in Mindanao - where there is a long history of lawlessness and Islamist rebellion.
Several armed splinter groups are pledging allegiance to Islamic State but none are known to have been endorsed as its Southeast Asian affiliate.
Elsewhere in the region, Indonesia has seen a resurgence in militancy.
Authorities believe I.S.
Ideology poses a real threat in the world's largest Muslim-majority country.
In Africa, Nigeria is host to Islamic State's West Africa Province - a Boko Haram splinter group which pledged allegiance to I.S.
It's focused on attacking and raiding military bases - making it the region's dominant militant group.
Egypt has seen no large attacks over the past year, but smaller incidents persist and the military is mounting a campaign against Islamist insurgents, mainly on the Sinai Peninsula.