I'm a massive fan of the Thousand-Year Blood War, so revisiting volume 48 is a trip. It ends with Ichigo arriving, but it's framed almost like a horror moment for the Quincy. He's not the hero swooping in; he's a storm that's finally made landfall after Yhwach's monologue about fear. The actual final scene is him facing off against Quilge Opie, which is awesome but not the biggest cliff.
The real hanging threads are about the Soul King itself. Yhwach's whole speech reveals the King as a linchpin, a 'thing' that maintains balance, and he plans to 'end that history.' That's a huge metaphysical bomb dropped. Also, we've just seen the full scale of the Wandenreich's first strike—the Seireitei is in ruins, captains are defeated, and the whole power structure is overturned. The cliffhanger is less a single moment and more the sheer, overwhelming 'what now?' of it all. Ichigo's there, but the war has already been lost in that first invasion.
Plus, there's a subtle one with Orihime and Chad staying in the human world. It feels like the story is deliberately isolating Ichigo's main friend group, setting up their own desperate run back into the action later.