Some people have found their way to use Cucumber with iOS through Calabash-iOS or Frank.
For me (this is a personal opinion it does not mean it is the same case for everyone) I think it is not the best way to do it; it is not native, and it requires either me or my QA colleagues to learn a new language (Ruby) for only this purpose; and it is only limit to UI.
And it has its own setup process and dependency stack.
So I started to look for any native-like implementation of Cucumber for Objective-C and Swift; in which I can still enjoy the awesome cucumber test cases technology while implementing the steps in a native language and see the result also in a native way like normal XC test cases.
However, I did not manage to find anything like what I was looking for.
I ended up developing the desired solution myself.
I named it Cucumberish. It is completely native, including how the test cases are implemented and executed;
you can find it on https://github.com/Ahmed-Ali/Cucumberish
I will be happy to answer any questions related to it.