Both are based on medical practice and has a gory feel.... The cross is mainly focused on revenge whilst Life is mainly focused on the business side of hospital. There is little to no romance in both show.
Both have operations with transplants. Both have a main character who cares deeply about patients. Both have a reasonable numbers of operations. One is more about revenge (cross), but overall both have elements like corruption and all.
Two must watch for who likes the genre.
They both have Genius Doctors in it who are working to find someone they loved in the past. I think Doctor Stranger is a little better than Cross both in acting and plot. Definitely check it out if you haven't seen it already. Oh and Lee Jong Suk is in it, so theres that.
Both dramas are korean dramas about doctors which are skilled professional in their field. But they resign and become doctors in prison in order to get revenge.