Inferno is the upcoming spring expansion for EVE Online. Players have probably noticed that everyday they log in, there is a new patch being installed; CCP is starting to roll out new content in preparation for Inferno.
Inferno will focus mostly on combat in EVE. The war declaration system, mercenaries, and factional warfare will all be overhauled to make more sense. Missile launchers, Amarr ships, and Minmatar ships are getting graphical updates, and there will also be major changes to the user interface and inventory systems.
Escalation is the aforementioned series of patches and new content that's coming to EVE ahead of Inferno. Here is breakdown of what has been changed so far:
If you want to see more details you can check out the full patch notes.