Coinbase will handle custody of stablecoin balances, manage conversion between digital tokens and fiat currency, and run on-chain settlement on its Base blockchain.

From the articleMarqeta and Coinbase Take Stablecoin Spending Mainstream | PYMNTS.comAlso in Coinbase, Marqeta to Launch Stablecoin Card Service for Businesses, Coinbase and Marqeta expand partnership to launch stablecoin-backed cards for enterprises, Coinbase, Marqeta Link Stablecoins With Global Card Payment Networks, Coinbase to power stablecoin-backed cards for Marqeta customers