tmux – Will session kill if not detached

The question I know is basic, but could not find an exact matching question in community.
The standard process of using tmux is – create a session, run command within and then detach the session. So existing ssh terminal will not kill our process.

My question is, if tmux session is created and a long command is running within it. But before detaching, if ssh session terminates, then will this tmux session persist or it will be killed too?