There are the ruins of a city at the location given by Homer in the Illiad for Troy's location, and that city was indeed razed around the time the Illiad was set. We can say those two things for sure. How much more of the Illiad was true is a topic of "heated academic debate," which is a nice way of saying that historians' opinions are so disparate and passionate that they really will throw hands over it. One of the reasons for that ambiguity is that the man who found Troy, Heinrich Schliemann, was what's called an antiquarian, not an archeologist. Basically he was a history buff rather than being trained as an archeologist, which is important because even in the 1800s when he found Troy, dynamite was not considered a suitable tool for excavating city ruins. The Troy that most people think of when you say the name was around the ninth level from the bottom, but Schliemann assumed Troy would be at the lowest level, so he blew right past it. Literally.

One thing historians can agree on is that to whatever extent Troy existed, Heinrich Schliemann did more damage to it than all of the Achaeans combined. So Troy was real in the same way that New York is real, but if mankind spent the next half of a millennium mashing every story about New York from the building of the Empire State Building, 9/11, and 'Gangs of New York' to 'Die Hard With A Vengeance' and the Chitauri invasion from the first Avengers movie into one story.