It will be extremely difficult for COD4 to do so. The only FPS to ever come near the 10 million mark was Half-Life, and that was when console FPS were really lacking and PC was the only real alternative for FPS gaming.
Nowadays FPS gaming is equally divided in the console and PC world, and contrary to the 10M+ sellers of PC - Starcraft, The Sims, The Sims2 and WoW, FPS gaming doesn't cater to a broader audience like these games do.
Current PC Build
CPU - i7 8700K 3.7 GHz (4.7 GHz turbo) 6 cores OC'd to 5.2 GHz with Watercooling (Hydro Series H110i) | MB - Gigabyte Z370 HD3P ATX | Gigabyte GTX 1080ti Gaming OC BLACK 11G (1657 MHz Boost Core / 11010 MHz Memory) | RAM - Corsair DIMM 32GB DDR4, 2400 MHz | PSU - Corsair CX650M (80+ Bronze) 650W | Audio - Asus Essence STX II 7.1 | Monitor - Samsung U28E590D 4K UHD, Freesync, 1 ms, 60 Hz, 28"
