h0ngcom

https://multiplayer.it/notizie/gran-turismo-espandersi-ancora-di-piu-polyphony-digital-dipendenti-ruolo-particolare.html (in Italian)

h0ngcom : The news said "Polyphony Digital is therefore not looking for software developers, but new employees who can help in the creation of collaborations and agreements with the world’s most famous car brands. This suggests that Gran Turismo, as a franchise, increasingly wants to connect to reality and propose means made specifically for the video game. "

So, yes, GT7 or GT8 will has some more car brands. The car brand may collab with GT such as make VGT car and/or become a new GT sponsorship.

With the word "world's most famous car brands" (that are not in GT7, or not in GT Universe), the video think it is likely to be Lotus.

H0ngcom also thinking about other brands such as Kia, Koenigsegg, Rolls-Royce, Maybach/Mercedes-Maybach, etc.

H0ngcom think Chinese brands are unlikely to be available in GT, due to there are too many brands and models, so GT will skip them, except the confirmed Xiaomi brand and (maybe) some Chinese brands under Geely (who has Volvo and Lotus).