Both are light romances and with plots that are an inversion of each other - MYIW has a modern day lead entering the world of a novel, MB has a novel lead entering the real world.
Both are mini dramas involving one of the leads entering a dream-like world in order to help their health, with the other lead soon entering the world to help them.
Both ML and FL character travel into a novel universe
Both FL is supporting character or extra's for the story.
Both the FL known to be evil character inside novel.