Inflatable tanks - like other inflatable objects, have been
around for decades - even world war 1 iirc.
With the advent of IR and Heat sensitive intel gathering equipment,
theyve added low-power heat emitters to them now so they dont show
up as cold on sensors.
The Bosnian Serbs / Serb / Jugoslavian Federal army used these to
great effect when NATO carried out strikes in the Balkans - where
NATO thought they were getting 98% hits on all targets, when the
pull out from Kosovo etc began, all the armoured units NATO thought
theyd hit pulled from their positions and went home intact. The
kills that NATO thought they had, for the most part, were decoys,
much like the tank above.