What is the difference between Celo and cUSD?

Hello there, I'm curious about the differences between Celo and cUSD. Could you elaborate on the key distinctions between these two entities? Specifically, how do they differ in terms of their functionality, purpose, and the ecosystem they operate within? Additionally, what are the main advantages or benefits of using each one, and how do they compare to other similar cryptocurrencies or stablecoins? I'm interested in understanding the nuances and unique features that set Celo and cUSD apart.