A top collection of first contact stories.
One that stands out is humans and aliens are on a planet at the same time. There are conflicts between the two groups. The aliens offer a peace treaty. A human anthropologist begs the human leaders to not accept the treaty. I will not give away the ending, but the anthropologist was correct.
Finder (or wombat, as us friends called him) did a great job of collecting these short stories by some of the top SF writers. Great food for thought of if/when we encounter aliens.
Jim Funaro, a cultural anthropologist, who started the Contact Conference on just this topic, has pointed out we have already met "aliens". Examples include Captain Cook in what is now Hawaii, and "civilization" encountering indigenous tribes in the South Pacific. In these cases, two groups who were alien to each other had at least one thing in common: someone died. If we do encounter non-humans, we can expect that will be the case.