The female lead lives in the modern Republic of Korea, while the male lead lives somewhere more outdated and dangerous. Both have travelled between their 2 'worlds'. Especially at the end of both dramas, when they have to go their separate ways and the main lead has to return to where he is from.
A man from another world enters a new world he isn’t familiar with, until he comes in contact with the female lead. After finding her, he clings to her and tells her where he is from - to which she thinks he is crazy. Until the female lead gets brought back into his world and finally believes him.
Both have virtual technology that you need to see via glasses/contacts. The plot of the drama revolves around the product undergoing a trial by the main character. Then without the creator’s consent, the product is released to the public (however not in the way the creator intended).