AGB stars are ideal IR targets because they are cool and bright. Most
of them escaped detection in optical or shallow IR surveys in the
eighties contributing to the puzzling missing number of AGB stars with
respect to theoretical predictions and former stages of
evolution. Observations and AGB models have advanced steadily in the
following decades providing us with an almost complete view of the AGB
stars in the Magellanic Clouds. Their properties are tracers of
structure and chemistry across galaxies. New surveys will be able to
fill-in the gaps, in terms of sensitivity and monitoring, providing
new constraints for the formation and evolution of the Magellanic
Clouds.