I guess it all depends on your definition of cold. Never got warmer than -12 F here yesterday and -28 F when I awakened. With two deer in the freezer (a place warmer than outside) I decided not to venture forth. But when I do hunt when it's below freezing, my primary concern is for trigger function. I degrease the inside parts and lubricate with dry lube of Teflon based spray. Use no oil or wax based lube on your rails. Then too you'll have to aclimate the scope well in advance and don't expose it to warmth before you hunt to keep it from fogging.
Equally important is to make sure all condensation gets wiped down after the hunt and bow is treated with anti-rust compound before storing.