Good afternoon, Monica,
Thank you for sending photographs of this chair to Mearto for appraisal.
The Milwaukee Chair company made these in very high numbers in the 1920s-40s. The leather inset was a more expensive option at the time. The chair is in pretty worn condition, particularly on the seat. It could be walnut, it could also be mahogany, though there probably wouldn't be any difference in value. It wont lose value if you refinish it, and could even increase in value a bit with a fresh stain, particularly on the seat.
I hope this answers your questions; please let us know if you have additional questions.