Pokémon has made a lot of additions to its classic battle formula over the years, though the foundation largely remains the same. The biggest changes are usually the new mechanics that come with each generation, like Mega Evolutions, Dynamaxing, and now, Terastallization. Even despite those changes, though, major lasting changes to the formula are far less common.
Source：https://www.cbr.com/pokemon-sv-19th-tera-type-facts-info-theory/
