How much do Cardiothoracic surgeons make? And how much school is required?

Quick answer to both of your questions: a lot. Lot of money, but also a lot of school.

>$500k/year median. Potentially less earlier, but >$500k pretty quick on a relative scale.

And I say "quick" in jest, to answer the second part of your question, it's a LOT of school:

4 year undergrad + 4 year med school + 5 years gen surg residency + 2-3 or more years cardio residency. Can be slightly less or more on the residency, but that's about the ballpark. You're looking at a minimum of like age 33 before you're actually making any real money.

Kicker to note: residents are paid, but not paid a LOT. Think like $50k, increasing as you get experience. More if you're ridiculously good at a top program maybe, but still a far cry from what you'd make elsewhere.

Second kicker to note: student loan interest :( If you're very lucky you can get a deferral on payments and interest during residency, otherwise you're looking at quickly accruing debt during your residency (when you're making very little money).