Step 1: If the product already exists in Shopify.
Step 2: Created the same product in PIM with same SKU used in Shopify.
Step 3: In the Shopify Connector, navigate to PIM2Shopify Link Refresh.
Once the sync is complete, the existing Shopify products will be updated instead of creating duplicate products.
To verify the mapping was successful, search for the product SKU in Shopify. There should be only one product associated with that SKU.