Ground and Steel types: weaknesses, resistances and Pokémon
Ground and Steel Pokémon take double damage from Fire, Water, Fighting and Ground moves, resist Rock, Normal, Flying, Psychic, Bug, Dragon, Steel and Fairy moves and are immune to Electric and Poison moves.
With 10 resistances and immunities against 4 weaknesses, it is a very solid defensive combination.
Ground moves are super effective against Fire, Electric, Poison, Rock and Steel and not very effective against Grass and Bug. Steel moves are super effective against Ice, Rock and Fairy and not very effective against Fire, Water, Electric and Steel.
To beat these Pokémon, your best pick is Fire, Water and Fighting moves. Avoid Rock, Normal, Flying and Psychic moves, which deal little or no damage.
There are 3 Pokémon with this combination, such as Steelix, Excadrill and Iron Treads.