After a beautiful reunion with Captain America, Bucky Barnes also meets his end, much you his fans' disappointment. It has been assumed that Bucky will one day take up the mantle of Captain America. Only time will tell if he will ever be back.
Image Source: wegotthiscovered.com
All the Guardians including the Star-Lord have disintegrated into nothingness in Avengers Infinity War. Now, it’s very unlikely that they’ll be forever be gone and will most probably be back in time for Avengers 4, especially since more Guardian movies are still to come.
Image Source: www.digitalspy.com
The S.H.I.E.L.D director Nick Fury who had launched the Avengers initiative also disintegrates in air, at the very ending of Avengers: Infinity War. But before that, he leaves a message for Captain Marvel, who is going to be a major part of Avengers 4. Fans also think Fury will be back especially since his arc with Captain Marvel is still unexplored.
Image Source: comicbook.com