Yes this is a myth
Contrary to popular belief, chameleons don't change their colors to blend in with their surroundings. In fact, although their natural camouflage serves several purposes, the primary function of the color shift is to alert neighbors of danger.

Chameleons take on shades that are within the range of colors that their species has evolved to possess, and these hues can include everything from aquamarine blue to pale pink and even patterned stripes and spots. Other chameleon species are limited to shifting between only a few specific colors, such as red, yellow and green.
So yes not everything we hear in childhood is true.😮