Look again. I'm betting there's some more sign close. That trail alone is sign that the area is used at least sometimes during the season, and should be enough to keep you looking. You might want to follow it a ways to see where it starts or ends.
A trail cam is great to build confidence that you are in the right area but not required for a successful hunt. Keep scouting. You don't have to find the animals now, just know that they are there.