Maids (2014)

I know they're different genres since one revolves around war and the other about the injustices slaves go through, but there are A LOT of similarities.

-Both female leads start off as lowly maids even if they weren't originally and were actually part of a higher class (in Maids she loses her status and in PA she loses her memory).
-Both female leads fight for justice and especially for the rights of the poor.
-They are both alone against the whole world basically.
-A cold male lead that hardly ever smiles.
-Romance that is important but isn't, however, the main focus.
-Female lead falls in love with the second male lead and hates the male lead at first.
-Good second male lead that becomes evil and corrupted towards the end but he still loves the female lead.
-In both dramas there's a depiction of the lives of maids and slaves who are treated badly because of the powerful nobles.
-Female lead is strong and isn't crazy in love with anyone.
-Second female lead is a noble in Maids and a Princess in PA and is in love with the second male lead.
-Delusional second female lead who was once nice but became evil, trying to make the female lead's life a hell bc of her love for the second male lead.
-Awful noble people are present in both.
-Once the female lead begins to trust the male lead, she discovers something that makes her lose her trust in him.

Like Bossam, in Maids we have a relatively well off female aristocrat who is uprooted from a sheltered life and must adjust to a peasant's reality.
The process is not smoothened by an initially harsh male lead who has lived that reality for most of his life, while hints are tossed around that his social status is something greater.
Similarly there is the presence of a former love interest of similar status to the female lead who is even after her fall from grace, still eager to keep the flame alive whatever the cost.

Maids is written by the same writer and features a young woman whose legal status and romances are affected by the political world around her.

Both themes are the lives of the servants who wait on the nobility, "The Confidant" in the Qing era of China and "Maids" in the Joseun era of Korea. Both dramas have nobles falling from grace and servants whose lives intertwine with those of their masters.

Both are historical dramas and the FLs are an inversion of each other - Maids is about a noblewoman who becomes a slave, and TToLO is about a slave who becomes a noblewoman.

Both female leads face downfall from noble/royal family to be servants/maids. Their assistants are also got killed. They also have two male leads pursuing them for love. They go through a lot of hardships and become stronger and stronger.

The backstory of GFB is quite similar to Maids, in that a spoiled nobleman loses status, suffers, and is forced to become a servant, causing her to become involved with a quiet, mysterious man.

Both FLs are sold as slaves/servants and fall into a completely different status in which they must learn how to survive and navigate. Both MLs are mysterious, quiet, and stoic guards and killers who have hidden secrets.

Both are historical dramas from the POV of the servant class, with tall and strong MLs and an initially spoiled and headstrong FL who has character growth.

I recommend this both drama because , Male lead and Female lead
try to solve problem
In one drama explosion and another student murder/suicide

They both deal with the same subject matter of maids and Oh Ji Ho is in both :D