Chainlink is an open source, decentralized oracle network that provides real world data to smart contracts on ANY block chain.
To understand the significance of Chainlink, one must first understand how Ethereum differentiates itself from Bitcoin by using smart contracts. Ethereum.org describes a smart contract as “a collection of code (its functions) and data (its state) that resides at a specific address on the Ethereum blockchain.” While users input the “code”, Chainlink provides the “data”.
Some of the functionalities we are seeing applied today include decentralized price feeds, verifiable random functions (VRF), random number generators (RNG), and connecting smart contracts to IoT devices, web APIs and cloud services. For example, Chainlink can connect to an Open Banking API to relay information regarding account information services or payment initiation services. Smart contracts can be programmed to execute when specific conditions are met, which could potentially save the consumer money.
Chainlink recently released their V2 white paper, you can read it HERE
Chainlink does not currently offer staking on their app, but this may very well be available in the future. I believe there are a couple platforms that offer staking, KuCoin and Crypto.com are two of them, but personally I like the LinkPool protocol much better (I plan on publishing an article regarding this soon). Chainlink can be added to liquidity pools to generate passive income from swap fees, however one must be careful of impermanence loss.