If you relocate to a different country, you will be able to retain your account as long as you are not moving to a country that IBKR is prohibited from transacting business in due to government sanctions.
However, even if relocating to a permissible country, you may be required to initiate a new application and request a manual transfer of eligible assets once your new application has been approved. Whether this step will be required depends upon the country you were residing in and the one that you are moving to as IBKR maintains multiple entities each of which has been formed to carry client accounts based upon local regulatory requirements and IBKR policies. You would need to contact your local Client Service Center to determine if your particular situation requires opening a new account.