During her fight against Mercury Yang is framed and everyone (minus beacon staff) fall for it even her sister and her team . Feeling betrayed Yang left Beacon and goes to Japan ( Remnant is on earth it's just isolated because most people fear grims) and join UA where she's place in 1a. After beacon win against Salem and Japan finish the War against the villain( most dead people will be alive it's not canon timeline) at beacon everyone know the truth and regret not trusting yang but two regret more ruby and Blake ( she love yang) . on day Miss goodwitch tell team Rwby and jnpr that they are going to go to Japan to help with the aftermath of the War and build good relashionship with the Heroes now that Salem and AFO are out of the way what will happen when the ex team mate see each other again ? ( i dont know much about rwby but i will try my best sorry for to the hardcore fan if i do some mistake)