The new No-Vary-Search header can be used to tell browsers that a query string like ?product_id=7 means the content on that URL is unique based on the query parameter, so cache pages like that individually. But also that a query string like ?utm_source=frontendmasters does not have unique content, so don’t cache it individually. (As explained […]

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The No-Vary-Search HTTP response header lets developers control browser caching behavior based on URL query parameters. It allows specifying which query parameters represent unique content (like ?product_id=7, which should be cached separately) versus tracking parameters (like ?utm_source=frontendmasters, which should not create separate cache entries).

Better Browser Caching with No-Vary-Search – Frontend Masters Blog