As of April 10, 2025, you can now give sales channel access to the Shop channel by selecting Shop in the Sales channel access section when you create a discount code.
Starting in May 2025 during experimentation, Shop will display your discount codes to some Shop customers on your product pages and the new aggregated discounts section in the Shop app.
You can start giving Shop access to your discount codes today, so that they will later display when the feature is available to customers in Shop.