Who would not leave the Tent of Meeting after the LORD spoke with Moses there?

Answer: Joshua

The LORD spoke to Moses face to face, as a man to his friend; his young assistant Joshua son of Nun would not leave the tent.

“Thus the LORD would speak to Moses face to face, as a man speaks to his friend. Then Moses would return to the camp, but his young assistant Joshua son of Nun would not leave the tent.”— Exodus 33:11 (BSB)