Can stereotype lead to confilict and war?

Stereotyping in itself won't likely lead to war, although it can generate conflict. Historically, it has been a factor leading up to wars, but the war is usually precipitated by other things.

A simple example would be the Nazi agenda that resulted in the war in Europe. Hitler's rhetoric condemning the Jews was really a stepping stone to obtain what he really wanted, which was to punish Europe and the US for Germany's humiliation resulting from the previous war and to gain power and control over as much territory as possible for his "Thousand Year Reich". Hitler used Europe's long standing antisemitism as a tool toward his goals, sometimes even quoting antisemitic statements of Martin Luther from the 1500s.