Interoperability is the ability of a blockchain to communicate, interact, and share information with external systems. In the blockchain world, most blockchains are more like closed systems than open systems that can interact freely. Interoperability is a big problem because it is difficult for users to move assets to other ecosystems.
However, there are already many interoperability technologies in place. The Bridge project, a generic messaging system, and an automatically connected blockchain ecosystem.
Some of the blockchain projects that are trying to solve this problem are LayerZero, Chainlink’s CCIP, Hop Protocol, and Wormhole. The Cosmos and Polkadot ecosystems already have unique interoperability systems that connect all the projects in their ecosystems.