Of course, success at Facebook or a similar company really depends on the role that you are applying for/working in at the company. Seeing as you are talking about computer science, I’ll talk about the relevance of computer science to a software developer or engineer role at Facebook.

Studying computer science of course gives you general software development and problem solving skills that are very applicable to a wide range of companies, not just Facebook. In most computer science courses you will learn multiple programming languages, which is useful knowledge to have, but also teaches you to be able to pick up different languages quickly which is an important skill in the software industry. More specific to Facebook, computer science degrees cover a lot of theory including, algorithms and data structures. Companies like Facebook tend to look for candidates who have a very strong grounding in this sort of theory, and questions will almost certainly be asked about these topics in interviews, so it’s really helpful to have studied them.

This is just a quick overview but hope it helps!