The Cave and Cliffs update will bring a much-requested update to the game. The general focus of the update is to redesign caves. This includes better cave generation that will improve the variety of the types of caves you will find. You may see large caverns, underground lakes, and waterfalls within the newly generated caves.
The update will include some new environments as well. You may find yourself in a Lush or Dripstone cave. Caves may also have crystal geodes, stalactites, stalagmites, and sculk sensor blocks.
These new environments also play into a new system being added to Minecraft, Archeology. You will be able to create new items, such as a telescope. But beware, a new monster called the Warden, is lurking in the caves. The interesting thing about the Warden is that it reacts to player movement. But fear not, you can tame an axolotl to aid you in battle!
Along with the update to caves, there will also be an update to the game's mountains. This update will make copper available to be mined, and mountain goats can be found in the mountains. Copper will also have an aging element in the game. If you build structures out of copper, over time, they will turn green.
The Caves and Cliffs update is set to launch the summer of 2021.