The reason they haven't been pushing COD as much as Destiny is that everyone knows about COD, it's been coming out every year for like 8 years straight (probably more, but I don't bother to check it, as it doesn't matter). so COD doesn't need as big of a marketing push as Destiny. However, I think Destiny might actually get a bonus from being a new franchise, because it's made by Bungie, and a lot of Sony fans have been waiting for a game made by Bungie that is availible on PS, while at the same time Bungie has a large fanbase from Xbox fans.
Conclusion: They will be close, I don't know who will be on top though.