If registered on a mailing list, there will be threads with always-continuing conversations. For long threads that are not important, mute the threads and they will no longer appear in the inbox. When mail arrives that includes user's address as a recipient or in Cc, mail will again appear in the inbox.
- Tap > > Gmail.
- The inbox opens.
- Touch and hold a conversation thread to add a checkmark to it, and then tap > Mute.
- The thread is now hidden.