If its not something easy.
Roll all your windows down then back up to make sure they are sealed.
Check sliding rear glass if you have it.
If a whistle can be heard each time you reach interstate speeds take it in for a fix.
Mine had bad weather stripping. The wind noise in mine was ridiculous at highway speeds. Several here complained...seach
wind noise.
The dealer replaced the right side front door weather stripping and the right side mirror, cured my excessive wind noise issues.
Pretty sure it was the top of the weatherstripping that was not sealing correct...
I tried to find it myself over one weekend. Used painters tape.
That gap in the weatherstripping around the windscreen is suspect.
You look. There are two small gaps about where the mirrors are.
Bigger suspect is the weatherstripping from where the whistle is coming from.
Take you tech for a ride on the interstate. They fixed mine.