Modern Warfare 2 Season 4 adds six new maps across modes

SOURCE:

https://www.oneesports.gg/call-of-duty/new-maps-modern-warfare-2-season-4/

"Three total Core maps will be added including Showdown and Kunstenaar District. The third and final map, Vondel Waterfront, won't come until the launch of Season 4 Reloaded." 

Kunstenaar District

"Showdown is a classic map that Call of Duty fans should recognize. The map is from 2007's Call of Duty 4, a fan-favorite, but the rest will be a nice new flavor for players to jump into.

Penthouse and Mercado will be added as two new Gunfight maps, and lastly, Mawizeh Marshlands and Ahkdar Village will be the new Battle maps.

All new maps coming during the new season:

• Showdown (Core map): launch
• Kunstenaar District (Core map): launch
• Mercado (Gunfight map): launch
• Penthouse (Gunfight map): launch
• Mawizeh Marshlands (Battle map): launch
• Ahkdar Village (Battle map): launch
• Vondel Waterfront (Core map): Reloaded"