Over the past year, Steve Rogers and Sam Wilson have both been pushed to their breaking points during their shared war against the Outer Circle and White Wolf's interdimensional army. While their struggles have brought the former closer than ever to the family he thought was long ago lost, the latter hasn't come out of things with nearly as much to show for them. In fact, all Sam is left with is the idea that he might not be enough to continue on as Captain America, although that doesn't mean he is ready to give it up, either.
Source：https://www.cbr.com/why-sam-wilson-wont-ever-be-ready-to-stop-being-captain-america/
