The first color to consider when styling your tan cashmere coat is black. Black is always a safe option, and it will pair well with both neutral and bright colors. If you're looking for a pop of color, try pairing your coat with a bright red or pink shirt. Another option is to wear a khaki or olive green shirt with your coat. These colors will create a natural contrast and will help to balance out your outfit. If you're feeling adventurous, you could also try styling your coat with some bold patterns or prints.