You should not be rewarded for surrendering.
Because if you do, that will make more players trying to just stay alive until the end.
However, if you don't get rewarded in some way, I don't see much reason to add it.
So, add a score requirement per round to be able to surrender and give a small reward if the enemy accepts.
But big enough reward than you would get from killing another 1-3 people (or atleast I would just try to keep on fighting to death).
In the end, it's only a matter of fun and it's not fun for those who are dead to wait for someone to die...
Also, the surrender option should only become available if you are heavily outnumbered with only a few teamates alive.
Poll