Chick-fil-A has long dominated the chicken sandwich category in fast food. After Popeyes Louisiana Kitchen launched its own version of the chicken sandwich, other fast food chains like Wendy's and Shake Shack got into the battle. McDonalds is testing a new chicken sandwich in Houston and Knoxville, and analysts have predicted the fast food chain will launch its chicken sandwich sometime in 2020. Who's winning the chicken sandwich wars and what will 2020 hold?