Jurassic Park is probably ridiculous. Most likely, cloned dinosaurs would not be able to survive in today's atmosphere for the same reasons we still have roaches and dragon flies but they are no longer huge like they once were.

https://www.smithsonianmag.com/science-nature/the-history-of...

Mammoths only went extinct 10k years ago. They might be viable, though I imagine they wouldn't be happy with what industrialization has done to the air.