Chain command blocks in Minecraft are one of three different command block types that can be utilized in-game.

Minecraft: How to use the /fill command on Bedrock Edition Here's how you can replace blocks on Minecraft Bedrock Edition and get a new block instead of an older one in the game.

Running '/execute as' from Command Blocks no longer inherits rotation from entity. Fixed a bug where Chain Command Blocks would not activate when Delay in Ticks was greater than 0.