Gazillion announced recently that Marvel Super Hero Squad would no longer be available to play after January 2017.
The game will, however, receive one final update this week. Gold will no longer be purchasable, but Gazillion is upping the drop rate for the in-game currency required to purchase just about everything. So in these last few months, it should be fairly easy to purchase just about anything your heart desires using the in-game methods. After the update, all characters will also be 20% off as well, for gold or this in-game currency, fractals.
At the end of the post, Gazillion also makes mention of their other super hero game, Marvel Heroes. None of this has any bearing on that game, which is still going strong.