What is the difference between Cronos and CRO?

Could you please elaborate on the fundamental distinctions between Cronos and CRO? I'm particularly interested in understanding their roles within the cryptocurrency ecosystem, as well as any notable differences in their functionalities, uses, or potential benefits for investors. Additionally, how do they interact with each other, if at all? And finally, which one of these two might be more suitable for specific investment strategies or use cases? Thank you for your clarification.