Instagram is experimenting with “Instagram Channels” feature, which is effectively a group messaging feature within the app where you can keep informed on particular subjects, brands, people, etc.
Instagram Channels is a “broadcast chat,” & will feature text, graphics, & polls within IG Direct.
Your list of IG Direct chats will include the channel once you’ve joined it. Following that, you can read & respond to chat messages, but you are unable to publish your own messages to the chat stream.