Doing CP, Corner Permutation, solves the corners in a way that they don't need any moves other than RU. This allows for 2GLL, which only needs RU moves to solve and is a subset of ZBLL and only requires 84 algs so it's a lot more manageable to learn compared to the full 493 ZBLL algs. But it lacks in recognition because you need to look at the corners and how they are in relation to each other, which isn't difficult just slower than doing a normal alg into ZB.
It differs from COLL because it doesn't worry if the corners are solved with yellow on top, it only cares about solving their permutation. This allows for only 2? algs to be used to solve the CP for example after solving F2L, since you either do an adjacent swap, like a T perm, or a diag swap, like a Y perm, or you have solved CP and don't need to do anything, then you can do 2GLL afterwards. That is really inefficient though since doing a PLL to solve CP takes a lot of moves compared to dedicated algs that can do it for way fewer moves or different ways to solve CP and another step like CEOR that does it at the start, or Epidote that does it while solving the last two edges. Doing CP like this makes it a lot better since you can do multiple things with one alg, but it also adds complexity and most people don't try to get good with it, or are just slower with it, but it can be really fun to do if you just want to use 2GLL and not worry about speed.