As of yet, this is unclear.

However, the most common theory is that Madame Gao is really Crane Mother, introduced in the The Iron Fist comics.

In the comics, she is the ruler of K'un Zi, one of the Seven Capital Cities of Heaven.

It is also possible that the MCU version may be from K'un Lun (also one of the Seven Capital Cities of Heaven), which would tie back to The Iron Fist, setting up a nice link between the shows.

The Seven Capital Cities of Heaven are all located somewhere in the Himalayas.

Of note, the symbol on the heroin baggies is the mark of Steel Serpent, another resident of K'un Lun, and another character from The Iron Fist. Crane Mother and Steel Serpent have worked together in the comics.