Well, we haven't seen a major war since Iraq, so I will go with that. We have seen, however, a Russian invasion pretty much shut down by mostly small arms. But the Russian army is small, too, so it doesn't count as a major war. Even Iraq wasn't really a major war by WW II standards.
Then you need to give a definition of what you say a "major war" is.
If WWII is your benchmark, then there has never been a major war since then, and will likely never be another until WWIII.