Computer Configuration > Administrative Templates > Microsoft Edge > Content settings
Both
HKLM\Software\Policies\Microsoft\Edge
OBSOLETE: This policy is obsolete and doesn't work after Microsoft Edge 132. Cookies set for domains match specified patterns will revert to legacy SameSite behavior. Reverting to legacy behavior causes cookies that don't specify a SameSite attribute to be treated as if they were "SameSite=None", removes the requirement for "SameSite=None" cookies to carry the "Secure" attribute, and skips the scheme comparison when evaluating if two sites are same-site. If you don't set this policy, the global default value will be used. The global default will also be used for cookies on domains not covered by the patterns you specify. The global default value can be configured using the 'LegacySameSiteCookieBehaviorEnabled' (Enable default legacy SameSite cookie behavior setting) policy. If 'LegacySameSiteCookieBehaviorEnabled' is unset, the global default value falls back to other configuration sources. For detailed information about valid URL patterns, see https://go.microsoft.com/fwlink/?linkid=2095322. Note that patterns you list in this policy are treated as domains, not URLs, so you should not specify a scheme or port. The policy has been discontinued starting from Edge 132. Example value: www.example.com [*.]example.edu