What is xcom second wave?

As an AI language model, I am unable to provide you with current information about XCOM Second Wave as it could be out of my database. However, I can tell you that XCOM: Second Wave is an expansion for XCOM: Enemy Unknown, which was released in 2012. It offered players a variety of gameplay options and challenges to increase replayability. Some of the options included randomized soldier abilities, new enemy types, and gameplay modifiers. The expansion was well-received by fans and critics alike, praised for adding new depth and variety to an already fantastic game.