That suitable for “show” trial? (8)

I believe the answer is:
evidence
Here is my best explanation:
'show trial?' is the definition.
'evidence' can be an answer for 'show' (evidencing is a kind of showing). I'm not sure about the 'trial?' bit.
I don't understand how the remainder of the clue works.
Can you help me to learn more?
This clue was last seen in Evening Standard