This is pretty tangential, but I just (1 hour ago) found out that iterm2 on Mac can integrate with tmux [1] if you run tmux with the argument "-CC", in a way that makes your tmux sessions map to the GUI windows / tabs in iterm2, including when using tmux on a remote machine via ssh.

I'm really excited about this, since I always forgot the hotkeys/commands for controlling tmux.

[1] https://iterm2.com/documentation-tmux-integration.html