I can see this on you Sterling. It is simple, elegant and classic - it won't date.
I used to have an unstructured trench and I wore it with very simple pieces underneath. Jeans and a nice tee, black pants and a blouse etc.. Perfect with flat shoes. Maybe a scarf but no need.
I think it would look gorgeous over a light pair of pants (white or bone or grey) and a similar toned top. It would also work with black pants and a light tee and light shoes. Or with olive pants.... I think it would be great to wear into meetings or conferences. I don't think it would work with a blazer or heavy knit under, but gorgeous with a fine knit.
I experimented with black and navy and found I can make it work. For me the simplest was to have at least two pieces in the minor colour. If it is only one it feels spotty to me - because navy and black are close it needs to look intentional.
eg. Black pants and jacket and bag - navy top and shoes
Black pants and bag and shoes, navy top and earrings.
black duster, black bag, navy top, pants and shoes
I think you can wear a third colour too - white, off white or maybe grey could work....