Darkness and emotional investment. Both stories have protagonists fighting against the injustice while morality of the methods used are in the gray area. Both series have a strong sense of comraderie/bromance where the guys take care and protect each other.

There is this subtle romance between the two main leads that makes me think of both the dramas. Also, the melancholy of the story which that subtle romance springs to life.

Definitely a slow burn on both ends but the connection between the leads is undeniable.

Both have the same screenwritter so you can expect a thrilling mystery and subtle yet deep romance. While one deals with memories and the other with time travel, both addresses the hardship of 'knowing too much' than an ordinary person and the pain of having to carry that with you.

They have a similar Vibe. If you're looking for something with the same kind of premise, this probably isn't it, but if you felt touched by how the story was told and what feeling it left you with, I'd say these two feel similar to me, to be watched side by side or one after another.