Will The Silver Surfer Be In Infinity War?

The answer is no. Recently the Silver Surfer showed up on somebody's cast list for Infinity War. This was probably a mistake, or somebody trying to stir up speculation. Disney is still negotiating the purchase of Fox (who owns the rights to Silver Surfer), and until the sale is final, there is always a chance it doesn't happen. There is a zero percent chance that the Surfer will be in Avengers 3. Anyone who thought that it was possible had their hopes crushed this week by the Russo brothers, who confirmed that the Silver Surfer won't appear in Infinity War.

It's possible that he could be in Avengers 4, except that the film has already wrapped shooting. They won't re-write the script or re-shoot major scenes, but they can probably add a simple cameo easily enough. If the Fox-Disney sale is completed in time, expect a few characters to make very brief and inconsequential cameos in the second film. The Silver Surfer plays a very important role in the comic edition, and Marvel will want to promote that franchise once they purchase the rights. But it's too late to make anything other than minor changes.

My best prediction for Avengers 4, you will get a Fox character in an end credits scene. Marvel is suggesting big changes after A4, so if they get the rights to some new characters, it will be a great opportunity for some kind of promotional cameo. The best way to introduce the Silver Surfer in an end credits scene will be one that is foreshadowing Galactus, that he's either coming to Earth sooner or later, but coming.