Recommendations

Not necessarily related but lovers of one show might enjoy both.
Both have that sci fi element mixed with fantasy and monsters.

Both these dramas are centered on a mythical
and immortal creature who used to be human and whose goal is to find the person who'll be able to help them end the curse they are subjected to.

The dramas are high-budgeted with good acting and high production value and cinematography.

The of this drama is Cheng Xiao. About Romance. Although this is about xianxia or wuxia, the female main lead of the two drama is the same, so watch this drama if you like Cheng Xiao. This drama is also had a good storyline and will not make you bored while watching.

Both are dramas with female leads which are cute, fragile ladies with glasses on a noble government position which are trying to straighten up a social outcast by trying to solve some of their problems. The main difference is that in Gokusen the heroine uses martial arts to scare of the people, which are trying to hurt the people she is trying to protect... In Zenkamono the heroine is left alone with the system.

Both movies are sport related.
Both movie showing sport in countryside, out of city environment
Showing pure, simple, joy in sport.
Team work.

Both are a female leads slice of dramas which operates with the daily work and life condition of a person. Danda Rin is about work conditions and Zenkamono is about people on probation.
Both are very inspiring dramas that shed lights on the importance of those people's jobs.

Both movies involve the main male lead went out of the city into very poor countryside and regroup the kids who are living in poverty, different background.
Heartwarming movie, must watch

Both Korean movie involve the main male lead and a group of underprivileged children.
The kind soft heart male lead in the countryside leading this kids into their dream
Heartwarming movie indeed

Both male lead are boxer.
Tough outside but soft hearted inside.
Heartwarming drama
Full of personality
Underground fight

Both has a male lead that has no choice but to return to boxing ring for money.
Tough male lead with soft hearted soul
Heartwarming Korean film indeed

Both movie has main male lead that is a boxer
Though sport, soft heart
Love romantic story
Drama, heartwarming, Japanese story

Both movies main male lead are boxer.
Both movie are quite romantic.
Sport related. Tough male lead
There is soft side of tough sport

Both movie involved main lead in the ring fight.
Lots of action
Both has romance
Love triangle
There are solve side of a tough man

Both movie about a downhill used to be famous player ended up at place out of main city.
The main lead ended up coaching a group of unfortunate kids
Inspired them, motivate them
Sport related

They both have the split personality trope and the main character are funny and cocky characters.

Hope you enjoy it as much as I did. The second season was also very good. It may have been a long time a go, but the show is still one of my favorite.