The first thing this tells us is that soon, you'll be able to purchase it on this store rather than Valve's Steam if you so wish. But the fact that the two games have been listed separately might be another hint that Modern Warfare Remastered will eventually be purchasable separately.
Fans have been asking for this ever since Activision announced that the Digital Deluxe Edition of Call of Duty: Infinite Warfare would feature a remaster of the critically acclaimed Call of Duty 4: Modern Warfare game from 2007, with improved textures, physically based rendering, high-dynamic range lighting and more.
Last month, we got another hint from Raven Software's Game Director David Pellas, who released the following statement to Gamereactor:
What we announced before today was that we were going to offer 10 maps on launch, and that’s still true. The announcement today is that the six remaining maps we are actually going to be delivering to anyone who purchases Modern Warfare Remastered, anyone who owns it or a version of Infinite Warfare that comes with it, they’re going to get all 16 of the maps for no additional cost.
However, Activision never confirmed any such thing yet; we'll be sure to update you if and when that officially changes.
It will also be interesting to see if this version of the games will feature cross-play with either PC Steam or Xbox One, as many other Windows Store games do.
Earlier today, we reported that Call of Duty: Modern Warfare Remastered will support Sony's PlayStation 4 Pro console with "richer textures" and "dynamic 4K graphics". Call of Duty: Infinite Warfare and the remaster will be available on PC, PlayStation 4 and Xbox One on November 4th, but PlayStation 4 gamers can already play the campaign of Modern Warfare Remastered if they pre-purchase the Legacy or Digital Deluxe Editions.