Confidential Assignment (2017)

the same movie but this is part 1 :)

Both are action thrillers that feature a begrudging partnership between a South Korean cop and a North Korean officer. The two gradually become a part of each other's lives in order to fulfill mutual goals while slowly building up a fragile trust, oftentimes to comedic effect.

Both deal with North-Korea and South-Korea and show the conflict of the two countries.
While Confidential Assignment has a North and a South-Korean Cop cooperating and shows a bit of the South Korean perspective of North Korea; Secretly, Greatly deals with North-Korean Soldiers and Spies undercover in South Korea.
Both movies have amazing action scenes, a great story and are also really funny.

Both are North Korean spies. Both want revenge on their loved ones murder. They both have the help of cops towards the end.

Both dramas have Hyun Bin as a lead who plays a north korean who is in the military and comes to south korea for a mission. During his partners up with a south korean detective and lives with his family.
The concept is very similar but Crash Landing is the romantic/humor version whereas Confidential Assignment is full with action and has nearly zero romance.