Good Start, but not great K-dramas show the same story, say revenge/ Will They Won't They Romance but in different settings like School, Office, Courts, Police Station etc.
The premise here is an advertisement agency and the protagonist is a single woman probably approaching her 40s. There is unlikely to be a romance as the main lead is a single woman and second lead is married woman. While the main heroine is serious and melancholy, second heroine is the cheerful one.
There are attempts at humour, but they are stale, seen many times on k dramas. So, the environment remains serious or heavy to be exact. Such premise can not be endured for long, it needs to be balanced with either comedy or romance or emotions.
The pilot is just okay but shows potential as the series goes on.
After watching the pilot, have to watch till 3rd episode before recommending it.