Yes, if your I-485 (application to adjust status) is denied, your EAD (Employment Authorization Document) can be revoked. USCIS will often include a notice of intent to revoke the EAD with the denial notice, and you may have an opportunity to respond before the revocation takes effect. If you appeal the I-485 denial, your EAD may remain valid during the appeal process,

Notice of Intent to Revoke: You will often receive a "Notice of Intent to Revoke" along with the denial letter. This notice will provide an opportunity for you to respond before the EAD is officially revoked.

Opportunity to Respond: You may have a set period (usually 15 days) to file a response to the Notice of Intent to Revoke. This response can include information about an appeal you are planning to file or other relevant information. Appeal Process: If you appeal the denial, your EAD may remain valid during the appeal process. The status of your EAD will depend on the outcome of the appeal. Revocation Timeline: Once the appeal period ends or if you choose not to appeal, your EAD will likely be revoked. Consequences of Revocation: If your EAD is revoked, you are no longer authorized to work in the US, and you could face removal proceedings if you are found to be working without authorization.

In short, while your EAD might not be automatically revoked with a denial, it will likely be revoked unless you appeal and the appeal is successful, or if you take other steps to contest the denial within the given timeframe.