Minecraft has announced a new update during Minecraft Live 2020. It's called the Caves & Cliff update, and when it arrives in Summer 2021 it will greatly diversify the game's cave systems. After this update, caves will be more varied, with new, unique blocks and mobs to gather and fight, too.

After this update, caves will feature more varied interiors, with lush caves, dripstone caves, and crystal geode caves mentioned. The game will feature improved cave generation, so that interiors will have more variety--you will encounter more narrow tunnels, cave lakes, and different environments than before. A new archelogy system is being implemented, so you can dig within caves for ruins and artifacts. Using a brush will let you extract fragile objects, while pretending that you're at the dig from the opening scene of Jurassic Park.

Players will also be able to encounter sculk sensor and stalactite/stalagmite blocks in the underground areas now. The sensors react to movement and emit a redstone signal, meaning that redstone can now be wireless. This should open up new possibilities for contraption builds.