Four years ago Assad, president of Syria, fired on peaceful protesters triggering a civil war. Several generals, officers, soldiers and political leaders quit the government and joined a secular opposition government, recognized by most of europe.
ISIS made up of foreign fighters from Afghanistan, Iraq and a number of european nations took advantage to capture land, carry out massacres, destroy places of worship, commit genocide and create a caliphate, sunni theocracy based government ruled by a cleric/fighter that goes by the name of baghdadi.
Syrian poured out of syria into Jordan to escape the fighting. More than half the syrian population is displaced, close to half a million have been killed and more than a quarter are refugees.
UN has run out of money to care for the refugees. They have been risking their lives by boat to reach safety. There are now refugees in greece, italy, jordan, turkey, lebanon and some have been getting aid and medical care from Israel.
Syria has bombed it's civilians, and palestinian refugee camps, with chemical weapons and barrel bombs. It has used torture and mass murder, both of which the country has a long history of. Syria has used their proxy army in Lebanon, hezbullah, to help them in their fight within Syria.
Recently a druze cleric, out spoken against Assad, was assassinated. Druze and Christians are not seeking Israel to allow refugees from these groups to enter the golan.
The Assad family and alwites, a shiite sect, have control Syria with an iron fist since the 70's.