These are both lovely and melodramatic dramas about love and how it changes you. They both feature different but very dynamic lead males and are written and acted.
same impossible love, the leading men are both boxers and then chaffeurs, they even have similar names (Bok Gu/ Dok Gu) XD
A Love to Kill is more intense and tragic, The Snow Queen is quiet and nostalgic, but they are both great!
They both have similar vibes (tsq being more tragic). In both dramas the leads meet when they were younger, became friends, and suddenly lost contact. They both meet in the future without realising who they are. The both also have a similar age gap.