The most common and most likely answer to this crossword clue is the 8 letter word COMRADES
I've seen this crossword clue in The Daily Telegraph
C
O
M
R
A
D
E
S
More clues leading to the result COMRADES
Buddy explains!

The straight part
We know that "fellow soldiers" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fellow soldiers = comrades.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 COMRADES mean?
COMRADES noun- A mate, companion, or associate.
- A companion in battle; fellow soldier.
- A fellow socialist, communist or other similarly politically aligned person.
- A gender-neutral title, functionally similar to "Mr.", "Mrs.", "Miss", "Ms." etc, in a communist or socialist state.
- To associate with in a friendly way.