The 5 millions talk again, this Isn't official numbers andwe don't even know if it is sold.
The only official numbers that we had is that Uncharted 4 sold 2.7 Millions(without Bundle, but with Digital) in the week of launch. We don't know nothing beyond that.
Microsoft would have using that 5 millions since the beggining of the year as a "Best selling exclusive of the generation" This is much better than marketing Mau
If Halo had sold 5+ millions in 3 months, we would know. There is simple no way that Halo didn't sold 70%+ of total sales on USA as usual. 3.5 Millions on NPD would chart more than it did
Halo 5 didn't had a lot of hours played on launch, 20 Millions in 3 days for something that sold millions at launch ?