Yes, in many situations a person with a pending Form I-485 may travel internationally, but they generally must obtain Advance Parole before leaving the United States. Advance Parole is issued through Form I-131 and allows an applicant for adjustment of status to return to the U.S. without the application being considered abandoned. If a person departs the country without Advance Parole while their I-485 is pending, USCIS may treat the adjustment application as abandoned unless the person holds certain dual-intent statuses like H-1B or L-1 and returns using that status. It is important to carry the Advance Parole document, passport, and adjustment receipt notices when traveling.