A chief scientific officer is a super smart person who works for a really important company or organization. They are kind of like a boss, but they don't tell people what to do. Instead, they use their big brain to help their company or organization figure out how to do things better.
For example, if the company makes medicine, the chief scientific officer might help them figure out how to make the medicine work better or how to make new medicines that can help cure diseases. Or if the organization does research, the chief scientific officer might help them figure out which projects to work on and how to do the research in the best way possible.
The chief scientific officer is really good at science. They went to school for a long time to learn all about it. They know about all sorts of things like chemistry, biology, physics, and math. They use this knowledge to make sure their company or organization does things that are really smart and helpful for the world.