Gross margin tells you how much of your net revenue you keep as gross profit. It is calculated in percentage terms to allow for easy comparisons — all you need to do is look at what has a higher gross margin (%) to determine what is more profitable to your bottom line.
In Segments, if your gross margin is showing 100%, then that means your gross profit is equal to your net revenue, which means we weren't able to find any CoGS.
Gross margin = Gross profit / Net revenue (* 100%)
In Shopify, gross margin can be derived from subtotal_price, refunds, and cost per item.