Heatproof is an ability in the Pokémon series that reduces damage from Fire-type moves by half. This ability is especially beneficial for Pokémon that have a weakness to Fire-type attacks. For example, Bronzong, a Steel/Psychic-type Pokémon that possesses Heatproof, takes neutral damage from Fire-type moves instead of the usual super effective damage, thanks to this ability.
In addition to mitigating damage from Fire-type moves, Heatproof also serves another valuable function: it halves the damage taken from burn status. Typically, when a Pokémon is burned, it suffers a reduction in its Attack stat and takes periodic damage over time. With Heatproof, the periodic damage from the burn is reduced by 50%, making it much more manageable.
Here are some additional interesting facts about Heatproof: