This year's Call of Duty has a weapon crafting system, because of course it does. As the video below demonstrates, each weapon has multiple prototypes, arranged under four rarity categories (common, rare, legendary and epic). These prototypes all have their own set of perks – one example offered in the trailer is a perk which grants a tactical nuke after every 25 player killstreak.
Or, if you'd prefer to build your own prototypes, that's where the crafting system comes in. Prototypes are built using salvage, a new currency which is earned in-game in a number of ways, though these ways aren't specified in the trailer.
Call of Duty: Infinite Warfare releases November 4. There's currently a beta in-progress, but it's restricted to those who pre-ordered the PS4 version. For the rest of us, there will no doubt be plenty of new details out soon.