Complex sentence: In March 2017, he was appointed to his current role at BMW, stepping down at the end of 2017, where he will continue on with BMW in an ambassadorial role until his official retirement in June 2018.
Split into simpler sentences: In March 2017, he was appointed to his current role at BMW. He is due to step at the end of 2017, and will continue on with BMW in an ambassadorial role until his official retirement in June 2018.