SOLVED. YA dystopian sci-fi(?) where there are only two humans, both kids, and everybody else is a robot

[Maddie]

Under Their SkinProbably read the book between 2015-2017 or around that time. A YA dystopian story focused on two kids (pretty sure they were siblings). They find out that everybody around them are actually robots and they are the only humans left. Don't remember much else except for that there was a point in the story where they go into a cave that has frozen human embryos in it.
My friend says that the parents were getting a divorce (?) and the cover was possibly gray if thats any help.
Thank you!

[Maddie]

book has been found! how can i move this post?

[Kris]

Glad you found your book, Maddie. I marked your request as Solved by clicking the small "edit" link after the topic header. Think only works on the full Desktop Website or Mobile Website (not the App).