What is 2000 jimmy front end hum noise?

You need to check the front wheel bearings, while driveing down the road stright turn the steering to the left and then to the right and listen to see if the hum noise changes, if not then both bearings are bad left and right sides. If the hum noise changes while turning to the left then right front bearings are bad , if hum noise changes while weaven to the right then left bearings are bad.