SuperData is not reliable at all and anyone folowing sales data for videogames knows 5 million is highly unlikely to be the all time record.
COD sells like 6-8 million in the US alone.
Not to discredit you entirely but you're being very vague with your statements. You say 5 million is highly unlikely but then claim Call of Duty sells better, then you throw an approximate estimate of 6-8 million, which isn't clear at all, and then you don't cite in which period does Call of Duty make those numbers.
My bet with The_Liquid_Laser: I think the Switch won't surpass the PS2 as the best selling system of all time. If it does, I'll play a game of a list that The_Liquid_Laser will provide, I will have to play it for 50 hours or complete it, whatever comes first.