Chainlink Cross-Chain Interoperability Protocol (CCIP) has officially launched on Avalanche, Ethereum, Optimism and Polygon mainnets. CCIP is currently in the "mainnet early access" phase and has been adopted by Synthetix and Aave. On July 20th, CCIP will be open to all developers on five testnets including Arbitrum Goerli, Avalanche Fuji, Ethereum Sepolia, Optimism Goerli, and Polygon Mumbai.