A number of Rivian executives in charge of production and battery development have visited Korea recently to prepare for a pilot production run in local facilities. After the battery development and production partnership with Samsung fell through, Rivian was reportedly still left with Korean suppliers as the only option to gain know-how and speed its American battery factory plans.
https://www.notebookcheck.net/Rivian-running-pilot-line-tests-for-its-own-U-S-battery-factory-in-order-to-achieve-EV-production-target-early.600832.0.html