Only a small minority of (unfortunately VOCAL) chabadniks believe that the Rebbe never died. Many believe that he would have been a potential candidate to be the messiah but since obviously moshiach isn't here yet it's not him... I find this generalization ("Chabad's messianic branch, which believes the last Lubavitcher rebbe, the late Menachem Mendel Schneerson, never actually died and is in fact the messiah.") rather offensive.
U.S., allies conduct 20 air strikes in Syria and Iraq against ISIS, says U.S. military (Reuters)
from the article: The day Chabad came to the Last Supper