While players who have completed the game have confirmed that Ada Wong doesn't in fact appear in Resident Evil Village, a series of sketches showing her involvement in the game were found in an artibook included with the Trauma Pack DLC.
In the sketches, Wong appears to take on the guise of a medieval plague doctor, sporting a long, beaked mask and cowl. She wields a crossbow, and looks built for stealth.
The images also reveal something of her involvement in the game. As revealed by the game's art director, she was essentially cut from the final game because of 'a number of conflicting scenarios'.
"An early plot point was to have Ada, disguising herself with a mask, help Ethan escape from his trial," the director said, as reported by GameSpot. The sketches show her shooting one of the game's antagonists, Heisenberg.
First appearing in Resident Evil 2, Wong often shows up in mysterious circumstances and runs to the beat of her own drum as somewhere between friend and foe.