The “Wolverine stack” is the nickname for taking BPC-157 and TB-500 together — named after the comic-book character who heals from any wound. The two are almost always sold and talked about as a pair, not on their own.
The reasoning people give for combining them: the two are thought to work through different routes — BPC-157 on tissue and gut repair, TB-500 on cell movement and new blood-vessel growth — so the pair is figured to cover more ground than either one alone.
No trial has tested the two together for tendon, ligament, or any other kind of healing. And because they’re nearly always taken as a pair, even user reports can’t separate what one did from the other. For what people say about each on its own, see the BPC-157 and TB-500 entries.