Although Abel City was merged with Asgard into Xgard during the Convergence, Sigma's Lab survived the process entirely intact because it happened to stand at the epicenter of the event, same goes to Avengers Tower when Marvel’s iteration of New York and Metro Cities merged into New Metro City. At the time of Sigma's demise, his lab was the place where most of Abel City's technology was developed. The most important piece of technology found now is the Capture Device, a device Sigma developed based on the same technology that allows X to copy a Reploid's skills and special weapons.
The stage is set within the laboratory itself, the fighters surrounded by several computer terminals and large monitor screens. A large, gray machine stands in the background behind the main computer terminal, recognized by its blue screen displays. Three mechanical hands hang above it inactive, and there's a large mechanical chamber at the right side wired to the Capture Device. In the background at the right side of the stage stands an automated robot assembly line, with mechanical hands putting together what appears to be Ultron Drones.
In this laboratory the Avengers manage to finish the Infinity Buster, and Thanos steals the Capture Device and modifies it so it can absorb the power from both mechanical and organical forms.