Tesla's board chair, Robyn Denholm, has warned that CEO Elon Musk may not stay if shareholders don't vote to approve Musk's nearly $1 trillion payout.

Tesla Board Chair Robyn Denholm said Elon Musk is key to the future of the EV maker as it focuses more on Full Self Driving and Optimus.

Warning comes as Glass Lewis and Institutional Shareholder Services urge shareholders to vote against the pay package.