What causes the lean, plus odd observation

2013 Yukon XL Denali. 191k, 6.2L, stock configuration.

Hi, this is my first post. so I'll give a little background. I have been hanging out at the Facebook GMC Yukon group with mixed results and found this group, which seems far more qualified! I consider myself a "Bolt on " mechanic - self taught home mechanic as a young adult working on 1960s cars, and have replaced a lot of suspension parts on these simple beauties. I am not looking to soup up my GMC, instead I am looking to keep it running a few more years as I love it, it still drives well, and it is cheaper than a new car. My biggest concern is it is rusting in rear quarter panels on both sides just above the trim strip, which is frustrating as it was garaged and pampered for the first 10/11 years of its life. I have a bit of a transmission issue but this is for a different time. Here is today's problem:

I noticed it is leaning towards driverside. It is a one inch lower on driver side when measuring from ground to center of fog lights. I went to measure clearance of tire in wheel well and noticed driver tire sits inside wheel well, while passenger tire sits outside wheel well. I would expect them to be the same. Tried to take photos but they wont help. Stock rims and tires. Only recent change is about 2 months ago had front brakes replaced- rotors, calipers and hoses. Passenger side had seized so replaced both sides. Is this likely suspension? Could it be related to the brakes?

What should I check to diagnose the problem, and what am I looking for - how do I know what maybe failing, or what should i measure, etc. Thanks so much in advance, and if I can contribute, I will.

Maybe rear track bar or bad bushings?
Honestly if it's a problem with tire wear or alignment, take a tape , maybe it got hit hard?

Look up GM lean on the ol' Google machine, you will find tons of info.

Very common for these trucks to sit lower on the driver's side.

You didn't specify front or rear but I assume both.

The fuel tank is on the driver's frame rail and there is always a driver in the driver's seat whenever the truck is in motion, this tends to fatigue the driver's side springs more in my opinion causing sag on that side.

Correct me if I'm wrong but, the "lean" effect was for silverados?

I notice it only on the front. When viewing on the back it seems OK. Also, this is something I noticed recently. I will monitor to see if it deteriorates. I'll hit the googler in the meantime.

Just Google "Chevy Lean" it is something that has been going on at least since the '80s with squarebodies, possibly earlier.

Measure the front spring length on both sides with the truck sitting level, and see if your difference in height is actually in the spring length itself.