According to IGN, Halo 5 “has outstripped every Halo game since 2007 in monthly active users - even before offering the full game as a free trial.”
I’ve been coming to these forums a lot over the last year and one argument I constantly see from people arguing against Halo 5 is supposedly that it has the smallest active user base of all Halo’s. Well, it looks like that may be a load of rubbish. Link to the article below.