Vanquisher are currently doing quite well, mainly thanks to Nilah being a powerful carry. The core concept of this comp is to run 4 Vanquisher + Frontline with Nilah as your main carry and Xayah as your secondary carry with leftover items. You can either run a mix of Sejuani, Shen, Taric, Sion as your frontline or instead resort to 4 Juggernaut by including Darius as one of your Vanquisher.
Your items are overall quite flexible, Nilah is great with increased range from items like RFC or Sniper's Focus, because she has a special auto attack. There is also an alternative build with 6 Juggernaut and 3x RFC on Nilah in the backline that works surprisingly well.
Nilah swipes her target and hits up to 3 units maximum. By increasing her range you have a much higher chance of always hitting 3 units and therefore increasing your damage. Due to Vanquisher having spell crit from their trait you can skip Infinity Edge and focus on RFC with damage or sustain items.
Xayah her ability has an amazing Armor shred that can easily bring her target down to 0 Armor and she also receives bonus mana from Ionia, so you want to make sure that you are running 3 Ionia to make her cast more often. She has a fairly long animation, so avoid giving her scaling items like Guinsoo, they work better on Nilah.