"Rollups have become the narrative focus of scaling Bitcoin lately, becoming the first thing to truly “steal the limelight” from the Lightning Network in terms of wider mindshare. Rollups aim to be an off-chain layer two that is not bound or constrained by the liquidity limitations that are central to the Lightning Network, i.e. end users required someone allocate (or “lend”) them funds ahead of time in order to be able to receive money, or intermediary routing nodes requiring channel balances that can facilitate the movement of the payment amount all the way from sender to receiver.

These systems were originally developed to function on Ethereum and other Turing complete systems, but as of late the focus has shifted to porting them to UTXO based blockchains such as Bitcoin. This article is not going to discuss the current state of things being implemented on Bitcoin currently, but going to discuss the function of an idealized rollup that people are aiming for in the long term depending on features Bitcoin currently does not support, namely the ability to verify Zero Knowledge Proofs (ZKPs) on Bitcoin directly."

Bitcoin Rollups - The Rock Or The Hard Place?
A look at the scalability limits of rollups, and the choices in making decisions regarding maximizing it.
https://bitcoinmagazine.com/technical/bitcoin-rollups-the-rock-or-the-hard-place

The article discusses the scalability limitations of rollups, which is a solution to address Ethereum's (smart contract test network) scalability issues. 

Ethereum's smart contract test network will eventually migrate its projects finally to Bitcoin's blockchain (production network blockchain). In due course, features that Bitcoin currently lacks, such as the ability to directly verify Zero Knowledge Proofs (ZKPs), will be supported on the Bitcoin production network blockchain. This development will enable the migration of Ethereum projects to the Bitcoin production network blockchain.

It's not a question of if this will happen but rather when it will occur. As these capabilities are implemented, the prospects for interoperability and seamless integration between the two networks will grow.