If you are a lawful permanent resident and are planning to travel outside of the U.S. for more than 6 months, you will need a re-entry document (Form I-131) to return to the U.S.
If you remain abroad for more than 6 months without filing for a re-entry permit, immigration may think you have abandoned your lawful permanent residency.
If you are a refugee, or currently have TPS or DACA, you may file this form to travel abroad. We do not recommend traveling outside of the U.S. until you have consulted with a reputable immigration attorney.
For more information, please click here: https://www.uscis.gov/i-131