Airliner 99 pilot reported an air turn back and precautionary landing after the landing gear would not retract during takeoff.

Narrative

On initial takeoff and upon achieving a positive rate of climb; I went to retract the landing gear and the gear handle would not move. I verified all circuit breakers were in. I attempted to move the gear handle up; out and up; and nothing would allow it to move. I moved the gear lock release located next to the handle and still could not get the gear to retract. At this time I contacted Dispatch and asked for an air return. Then Notified ATC and they gave me vectors for landing on XXL and ZZZ. Landed and taxied back to the cutter Ramp without incident. Unsure. Maintenance had just performed maintenance on the gear handle sub panel for the landing gear lights. This could be a contributing factor. Or; I simply missed the operation of something. Though; I'm not sure what that could be. I have never had a landing gear handle fail to move before. Attempt to trouble shoot by checking circuit breakers and trying to move the handle many times and different ways to no avail. I am not sure. Some how being able to check gear operation before flight. That doesn't seem realistic or practical for every flight. So; I'm not sure. Open to suggestions.