Both involve corrupt politicians, crazy royals, and concubines. The Treacherous is a lot more gritty, but both explore themes of revenge, lust, greed, desire, and power.

This is kind of like a watered down bootleg version of Untold Scandal, but the baseline plot is very similar with both stories surrounding seduction and deception. The Celebrated Gisaeng is MUCH more lighthearted and lacks the depth and drama that Untold Scandal has.