Por Favor Volte, Ahjussi (2016)

Both dramas revolve around heavenly beings trying to protect humans on Earth.
Please Come Back, Mister is not really a romance, but the comedy and tropes are similar.
They both have mystery components and executing the will of a higher being such as God and fate.

Please come back Mister has body possession by two old ajussis who are reincarnated. They act weird and it's really fun to see them, yet The day of becoming You has no reincarnation but they swap bodies.

Both have body swap and there is area between afterlife and earth
But one is about revenge and normal life whereas the other is supernatural and ghosts.

The leads are the same. Sang Doo is the first main role for Rain and he acted very well. Rain acted a father who adored his daughter and his love in both dramas. CBM is more hilarious than Sang Doo. They don't have same plots and Rain's character in Sang Doo is more miserable.
Both dramas are must-watch! ;)

~Not Bl or Gl...
•Story is completely different but one of MLs ended up being reincarnated as female