Vayne is a self-peeling Sniper that removes aggro from herself every time she autos after her ability's activation, in exchange, her damage output is lower than Jhin's, and thus is far more item dependent, specially due to her Cybernetic trait.
She desperately needs Last Whisper to cut trough front lines, and Infinity Edge to burst down squishy carry consistently.
The Last item can be recommended to be Runaan's Hurricane, to allow her to deal with multiple targets quickly.
As a team/trait set-up, Vayne largely benefits from 4/6 Chrono in addition to 3 Cybernetics, 6 Cyber is not optimal as Vayne needs more Attack Speed than raw Attack Damage since Sniper and Cyber on top of her ability's scaling already cover her need for damage.
New Ability:Active - Final Hour: Focuses for 10 (× AP) seconds, tumbling away from her target immediately and every third attack thereafter. When she tumbles, she becomes invisible and her next basic attack deals 175 / 200 / 225% ADphysical damage.
Passive - Silver Bolts: Basic attacks apply a Silver Bolts stack. Attacking a new enemy removes all her stacks from the previous target. The third stack consumes them all to deal 8 / 10 / 12% of target's maximum healthbonus true damage.