Highlight complementary product offerings and encourage customers to subscribe to additional products using the Checkout Cross-sell feature. Checkout Cross-sell is available for all stores on the Recharge Pro plan and using Shopify Plus.

Checkout Cross-sell is a Subscription Experience that showcases purchasable one-time and subscription products right at the checkout using the Recharge Subscription Cross-sell app block so customers can easily add additional products to their checkout order. 

You can read more about this feature on the Cross-sell products at checkout Help Center guide.