How to Get Rid of the Smoke Smell from a Backpack?

One thing you can try, and should not damage it if the trim is the only thing that is leather. Turn it inside out and put it in the dryer on low heat with a Drycleaners Secret sheet (home drycleaning cloth). I cannot afford to clean all of my suits every week so I use these to freshen them after wearing. The sheets have removed any smoke smell from being around smokers. Of course, you can also try the baking soda suggestion. I do use baking soda for odor control, though it may take time.

Maybe you could mist it with plain water and put it out to dry in the sun?

suds up a sponge with original scent dial(gold) and wipe the fabric down. Crush newspaper and loosely stuff it to dry. This worked for a briefcase I had.

i wonder if a small dish of baking soda would pull the smell out i would bet you would need to put it in a 2 gallon ziploc bag with the dish of baking soda for a couple of days