Polkadot and Cardano are building a partnership.

A strategic relationship has been formed between $DOT and $ADA to make blockchain technology more interoperable and scalable.
Polkadot's Substrate is a modular design that is the base for the Polkadot software development kit. Cardano's "partner chain" project will be connected to it. By offering a flexible solution for a number of blockchain ecosystems and chains, the goal is to show that Substrate can have an effect across the Web3 area.
The agreement will help solve problems like vendor lock-in, connectivity, security, and tokenomics.