Early in WWII there was a push to find a lightweight, highly mobile tank destroyer. There were tests done, mounting the 3 inch gun on the M3 Stuart chassis under the designations T50, T56 and T57. The gun sadly was too heavy for the chassis. As a follow up, the 75mm gun from the Sherman was mounted in the turret of the M8 HMC which was based on the M5 Light Tank. Test were so encouraging that plans were made to go into limited production until a new vehicle, then under development was ready. The new vehicle, the T70, mounted the 76mm gun and was ready for service before the needed modifications could be made to the M8 HMCs. The T70 would go on to be accepted into service as the M18 Hellcat.
Ingame, because of the open turret and the thin armor it’s recommended to use this tank mainly for ambushes.