You are correct. Unfortunately, the ‘leader’ of the Islamic State military died (I believe it was probably in the year 666) and there is no new ‘head of the Islamic State’.
ISIS will soon set up shop in Iran or Iraq as their “nation” with a ‘king’ and our next POTUS should invade it and eradicate all of them.
IS does not recognize 21st century national borders. As of right now, spread out like they are, THAT is “their” nation and they intend to grow it.