Structurally they are similar enough that we can communicate. The discovery would be altering our science, but every attempt to exchange beyond technicalities and niceties is somehow incredibly boring to both sides.
After the initial awe, it would be like, yeah, we know aliens.
But what if they taste delicious?
I’m pretty sure humanity in space will go full dog mode, meaning we will have two basic questions:
Yes to both.
Flip them and you’ve got essentially humanity’s history