On the one hand, the religions will never in harmony with each other, as they have contradictory beliefs about Jesus and Mohammed.
But that does not mean that Christians and Muslims cannot get along with each other. There was a period of time in medieval Spain when the two did exactly that. Of course, it did not last.
On a more local level, we have a number of Islamic refugees here, in a very Christian area. Of course there have been, sadly, some hostilities, but I have also seen many examples of the two groups getting along in a friendly way.