Does your Infiniti Q50 have a bad odor or smell to it when you get inside your car? When I would get into my Q50 and the air would come on it would automatically start to smell humid and a little like body odor in a weird way.
I took the car to the dealer and they said it was the and they said it was the in-cabin air filter that needed to be replaced. So instead of having it done there I went over to Amazon and found one for around $13.00 plus shipping and handling.
Here is a video that I used which shows how to replace Cabin Air Filter on a 2014-2018 Infiniti Q50 (view instructions).