little changes here and there
Some of the most common images of humans and aliens together are the fake autopsy of Area 51 or even the other way around with humans captured by aliens.
My Idea would be to bring aliens and humans together doing an autopsy of a third party.
For the third party, I thought of Nature since we are destroying the environment while developing and so did the Alien race. This makes Nature the new Alien.
After developing to a higher technical level they try to save what is left, together.