Black Beard is after something, right after he read the "BIG NEWS". It is related to marines, which would mean marines are also invovled in this. It can also be the same case, why marines are mobilizing their forces and why they won't come to Wano, because they have something "more important" to do right now.
- Some people are saying that he is after EX 7 Worlords, but i'm not buying it. If you look at the list, no one of Worlords will join BB Crew. - Some people are saying that he is after Ancient Weapons. I'm not buying it either. Only fishman people know about Shirahoshi, besides SHC and Caribou. We saw the story of Caribou and he wasn't able to share this information with anyone, yet. Pluto plans got lost, so there could posibly be only Uranus.

- Some people say that he is after some devil fruits. I think it's a good idea, but after Who's Who im story, i think that Black Beard and Marines are after the same Devil Fruit, not the Fruits. I could see it that Black Beard would want to get specific Zoan Fruit that Marines want to protect.

So, Black Beard probably after some specific Devil Fruit or Ancient Weapon Uranus. I'm not buying it that he will come to Wano randomly.