The Sacrifice

The Sacrifice is an upcoming three-map DLC for both Left 4 Dead and Left 4 Dead 2.

It will be the sixth and so far last campaign for Left 4 Dead. Whether or not there will be another later DLC is unknown.
 * If downloaded for Left 4 Dead, you will gain a new campaign, called The Sacrifice, which is played as the original Survivors, and end with a member of the team sacrificing themselves.
 * If downloaded for Left 4 Dead 2, you will gain The Sacrifice, along with No Mercy being playable. In addition, players will take control as the original Survivors, but retain all the new weapons from Left 4 Dead 2, such as the M60 and Katana, along with the Special Infected from Left 4 Dead 2.