Cyber security uses multiple layers of defenses for protecting information. If one layer is defeated then the next one should catch it.
Newbie: So when it’s cold outside, we put layers of clothes on to stay warm. If the cold was hackers, and the clothes were our protections you can get a basic idea of the layering principle. The more ways you block intruders, the fewer ways they can get in. The added benefit is that even if they get past one protection, they are going to get stumped by another one.