Death has been destroyed, but one day it will be in a totally literal sense
----the Devil, who has the power of death has BEEN defeated--but Satan has been allowed to continue on earth--and is being defeated and cornered as each day marches on. After the rapture he will be imprisoned for 1000 years, and then released one more time upon the earth. (See REV. 20).
Then, at the very end of time, death will finally be "destroyed" in a very real sense:
The last thing thrown into the Lake of Fire is this:
"The dead were judged according to what they had done as recorded in the books. The sea gave up the dead that were in it, and death and Hades gave up the dead that were in them, and each person was judged according to what they had done. Then death and Hades were thrown into the lake of fire. The lake of fire is the second death". (Rev. 20:13,14)
Note: death and hell are the last things thrown into the lake of fire--and everyone not written in the book of life. So, the last enemy to be destroyed is death and hell---but this will happen far after the Rapture and the 1000 year reign of Christ on earth.