I'm not necessarily sure we can call the Syrian Civil War the largest humanitarian crisis since the second world war, but i do think that it's potentially one of the worst of the current day. Overall it will be interesting to see how different countries, such as the Western powers, Russia, and Iran in particular, respond over the next few years. With Russia backing the Assad regime and deploying advanced weapon systems - the Su-57, S-400, and even the Russian aircraft carrier Admiral Kuznetsov, into the country it is unlikely that we will see a resolution to the conflict through diplomatic means for quite some time. This could potentially mean a very bleak future for the Syrian people, as violence in the country is less and less between the government and islamic insurgents and more and more between the government and antigovernment forces. In many ways, the geopolitical conflict in Syria seems to be an attempt by Russia to not only reassert themselves on the international stage, but drive the Western powers into another "frozen conflict", not unlike those in Ukraine, the Caucuses, and Moldova.