The joke is:
A: Look at my knees
B: What kind of knees are these?
A: Chi-neese

“Chinese, Japanese, dirty knees, look at these.” Was a rhyme used with slant eye gestures to make fun of Asians.

The lesson is:
When you make movies for The World, know The World is watching you. https://t.co/TtII5HNzAI

— Ludi Lin (@ludi_lin) December 5, 2020