The most common and most likely answer to this crossword clue is the 5 letter word COULD
C
O
U
L
D
More clues leading to the result COULD
Buddy explains!

The straight part
We know that "Can future" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case can future = could.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does COULD mean?
COULD verb- (auxiliary verb, defective) To know how to; to be able to.
- (modal auxiliary verb, defective) May; to be permitted or enabled to.
- (modal auxiliary verb, defective) To have the potential to; be possible.
- (auxiliary verb, defective) Used with verbs of perception.
- To know.
- Something that could happen, or could be the case, under different circumstances; a potentiality.