ISIS has never attempted to attack Israel, and claims that that is because the Palestinian struggle is not more important that any other Muslim struggle. I’d say, though, that it’s because they know they’d get their collective clock cleaned, and they never were that good militarily. They’ve mostly been getting their ass kicked for the last year, and Abu Bakr al-Baghdadi was severely wounded by an air strike recently, or actually killed, depending on which sources you read. Attacking Israel would be the biggest mistake they could make, and they’ve made some doozies.