ChainLink (LINK) is the native currency of the ChainLink platform. It represents an ERC-20 token is listed on multiple exchanges paired against major cryptos. At the time of writing, you can trade LINK against the fiat USD currency on Coinbase Pro.
Smart contracts are not able to access data on their own. Since connecting these contracts to data via node is deemed as a point of failure, using a decentralized service could be a solution.
Therefore, the ChainLink project sees its mission in the integration of the off-chain data into smart contracts through a reliable decentralized oracle network. LINK tokens hit the market in 2017 and the currency quickly made its way to the top 50 cryptocurrencies by market cap. Later it reached the top 20. ChainLink partners with a large banking network SWIFT.