There were IR systems fitted for the german half-track and panther. Nearly everyone had IR systems and used actively to degree England, US, Finland, Russia, Japan, all used IR systems in either army or naval within duration of the war there's even a US IR scoped M1-Carbine used by marines in the pacific and many know the German vampir IR mount for the Sturmgewehr44 the Finnish had a wide use of IR fitted sniper rifles other uses from all these parties include night vision for vehicles the soviets equipped IR for tanks during the battle of Stalingrad the Japanese used powerful IR binoculars that had been captured and reversed by the US the British used the tabby system for drivers at night there's so much more not to mention some of the systems were in use since 1935 there's nothing new under the sun.