Emperor Philippa Georgiou (Michelle Yeoh) is a character who was of great importance to Star Trek: Discovery, but her existence has likely been redacted from Starfleet's history by the time of Star Trek: The Next Generation. After the USS Discovery traveled 930 years into the future at the end of Star Trek: Discovery season 2, knowledge of the Crossfield Class ship was classified by Starfleet with its records redacted by Lt. Spock (Ethan Peck) to protect his adopted sister, Commander Michael Burnham (Sonequa Martin-Green). Since Emperor Georgiou traveled to the future with the Discovery crew, her role in stopping the malevolent A.I. Control has likely also been redacted and eventually forgotten.

https://screenrant.com/star-trek-emperor-georgiou-tng-era-section-31/