Such as Helen she is beloved to be the daughter of Zeus but obviously that is not true( I think). There’s various account that achilies was not real, And there is various mentions of the Greek gods helping/intervening in the war when in current time people do not believe this
The short answer is that a city called Wilusa/Ilion has been identified as "Troy" and has been excavated, and the excavations show that it was burned/razed during the time the events in the Iliad and Odyssey are set. But the Iliad and Odyssey are fictional retellings of an event that use depictions of events from a much later period of time in Greek history to tell a tale of the older war. Think of a fictionalized telling of, say, the time of Henry VIII when his armies wear uniforms from the Second World War and the author invents new characters to tell the tale of the greedy king.
These older answers from our FAQ may explain this better:
https://www.reddit.com/r/AskHistorians/comments/44pzp2/accuracy_of_troy/