I consider Tunnel as one of my favorite crime/mystery genre, and Tell Me What You Saw has the potential to be just as awesome~

Signal is my representative kdrama in the thriller mystery genre, and Tell Me What You Saw gave off that vibe, also the start of the 1st ep really reminded me of signal too

the main plot for both dramas involve dancing. and they also use dancing as a way to express their true selves, while it also connects the unlikeliest people in beautiful friendship

both had the "extremely" tall female lead, and "extremely" short male lead that end up partnered together, which adds to their self consciousness, and the story follows them as they try to grow

from the trailer both seem like time traveling mystery crime dramas about people trying to find justice through time

both have Kim Kang Woo, and both have unique never seen before in kdramas/kmovies plots. one is a futuristic alien story and the other is a supernatural urban fantasy kind of a story

both plots are about people that "accidentally" become detectives. they are both comedy mystery genres and overall a fun watch

I'll just connect both 1st seasons together. they are both fun mystery variety shows that lets the viewers guess along side the participating members.

both dramas are female centered, and their comedic sense is slightly similar. overall both are a fun watch

I love recommending/connecting dramas that have my sense of comedy? they are not over the top but they are ridicules and funny. kim bomi and Jung Bok Dong are kinda similar too xD

both male leads are the sweet dorky kind. while the female leads are different from the usual representation of a female character in dramaworld.
both couple also are a "friends to lovers" kind of a ship~

both kinda break "gender roles"? SWDBS has a freakishly strong female lead that saved the day and caches the male lead when he falls. while TTON has a male lead that disguises as a woman and he looks soft and pretty.