Not even sure why we're comparing the PS4 CoD to Halo... It's a rather terrible comparison to be honest. A more interesting comparison would be XO BO3 vs Halo sales first year and LTD. When we look at 360 BO1 and BO2 vs. Halo Reach and Halo 4 we can see that both CoD titles crushed Halo in sales on that platform alone.
The approach I'll take to this is solely based on 2 situations:
BO3 Exclusive to PS4/XB1 only:
I'll take BO3 beating Halo on both platforms
BO3 on older gen:
I'll take Halo winning on XB1, because that difference will make the difference. Plus Halo isn't annualized, so we might see more sales after year 1 compared to BO3. As for PS4... US: Halo Easily.... WW: Quite close to a virtual tie.
Current gaming platforms - Switch, PlayStation 4, Xbox One, Wii U, New 3DS, PC







