The Ethereum merge, also referred to as Ethereum 2.0, is an upgrade to the Ethereum blockchain that has improved the overall performance and security of the network. This upgrade includes a switch from a Proof-of-Work (PoW) consensus mechanism to a Proof-of-Stake (PoS) consensus mechanism, which is more energy-efficient and secure. The Ethereum merge aims to build a more scalable, sustainable, and secure blockchain infrastructure for decentralized applications and financial use cases.