It's not always easy to put together the perfect Pokémon team. It's ideal to create a team that contains Pokémon of varying types in order to protect them against a multitude of enemies, but doesn't lose the opportunity to dish out super effective attacks. With many Pokémon falling under more than one type, these combinations can make Pokémon vulnerable to more types than expected.
Source：https://www.cbr.com/pokemon-fewest-type-weaknesses/
