For me, it was months jobless and isolated at a parent's house in the middle of nowhere.
For others, not battling means not getting out of bed, and for people facing other "demons" (what a bad word) not fighting might mean to continue to consume drugs or alcohol, or to keep not eating, or eating too much.
For me, it goes "I'm feeling depressed. Okay, I feel depressed. That's interesting. Now what is it that I must do right now at this moment? Get out of bed. Okay, done. I'm still depressed, but what's next?"
In other words, I don't bother fighting it or avoiding it. I just acknowledge it and then figure what needs to be done next.
To me, that is fighting.
Could be this is a cultural problem. In our culture we’re supposed to like work and everybody is expected to shut up.
Running is weak also, but insomuch as all you can do is fight and claw your way out of depression[^], long runs, in my experience, can aid to some degree.
[^]Which may very well be a symptom of something(s) we don't understand yet, rather than a disease.