Damn mate that's some high quality work right there. Color and shading looks amazing overall, REALLY nicely done. It's mesmerizing, and the folds overall are so nice to look at as well.
If I had to nitpick on something, it'd probably be a bit on the texture side. The skin is a bit too smooth and the shirt texture seems like it should be a bit more rough as well. Not that I could do any better if I'm being honest, but that's the only point that kind of stands out.
How to get that little texture is hard to say though. I personally use texture assests and blend them in partially, or try to play around a bit with burshes, though as I said, I'm not sure I could do any better.