expression, i-adjective
gaining nothing by; getting nowhere by
Used in the pattern ～ても何も出ない to mean that doing something yields no benefit or progress. Often follows a verb in ても form.
今さら文句を言っても何も出ない。
Complaining now won't get you anywhere.
慌てても何も出ないから、落ち着いて考えよう
Panicking won't help, so let's calm down and think.
仕方がない expresses that something can't be helped or is unavoidable, while 何も出ない specifically means that an action yields no result or benefit.
A fixed expression composed of 何も (nothing) + 出ない (does not come out), literally 'nothing comes out'. The phrase is idiomatic and its origin is straightforward from its components.