An earlier museum in the citadel also called itself "Panorama". I do not know if in view of works at the citadel it will return.
Thís museum has a huge panorama but much more. Its name was a bit unclear, the shortest version in Turkish is “Panorama 25 Aralik Müzesi”, but longer names can be found, most probably “Panorama 25 Aralık Gaziantep Savunması Kahramanlık Panoraması ve Müzesi”. An English language site has “Panorama December 25 Gaziantep defense, Heroism Panorama and Museum”. Indeed not ONLY war scenes are displayed, but also more general information about the town’s history.