All Activision Blizzard titles are on sale right now on Battle.net, including Modern Warfare II and other Call of Duty titles.

It's the most wonderful, but expensive, time of the year. With our wallets being drained left right and center it's nice to get hefty discounts on video games. Battle.net has begun its annual Holiday Sale with many titles including Call of Duty: Modern Warfare II.
The Holiday Sale will run from now till 2 January 2023.
World of Warcraft
Limited-time offer: Get an extra 30 Days of Game Time when you buy Dragonflight
Dragonflight Expansion Trial: For a limited time, play as a Dracthyr Evoker with only your subscription or game time
The Heartwarming Pack: up to 60% off
Wrath of the Lich King Classic Northrend Heroic Upgrade: up to 25% off
Wrath of the Lich King Classic Northrend Epic Upgrade: up to 25% off
Select pets, toys, mounts, and game services: up to 50% off
Call of Duty
Call of Duty: Modern Warfare II: up to 15% off
Call of Duty: Modern Warfare II - Vault Edition: up to 20% off
Call of Duty: Vanguard: up to 50% off
Call of Duty: Black Ops Cold War: up to 67% off
Call of Duty: Modern Warfare: up to 67% off
Call of Duty: Black Ops 4: up to 67% off
Call of Duty: Black Ops 4 Digital Deluxe: up to 60% off
Diablo
Diablo 2: Resurrected: up to 67% off
Diablo 2: Resurrected - Prime Evil Collection: up to 67% off
Diablo 3: up to 50% off
Diablo 3: Reaper of Souls: up to 50% off
Diablo 3: Reaper of Souls Digital Deluxe: up to 25% off
Diablo 3: Battle Chest: up to 33% off
Diablo 3: Eternal Collection: up to 25% off
Diablo 3: Rise of the Necromancer: up to 33% off
Overwatch
Overwatch 2 Watchpoint Pack: up to 40% off
StarCraft
StarCraft Remastered: Cartooned Upgrade: up to 25% off
StarCraft Remastered: up to 50% off
StarCraft Remastered Cartooned Bundle: up to 30% off
Nova Covert Ops Bundle: up to 33% off
StarCraft II Campaign Collection: up to 25% off
StarCraft II Campaign Collection Digital Deluxe: up to 33% off
BlizzCon
Blizzard Arcade Collection: up to 50% off
Crash Bandicoot
Crash 4: It's About Time: up to 50% off