The latest US spending bill allows NASA to not use the SLS for the Europa Clipper space mission. If NASA determines an SLS is not suitable for Europa Clipper, NASA can then conduct a "full and open competition" for a commercial alternative. This basically means that NASA can use a SpaceX Falcon Heavy or SpaceX Super Heavy Launch Vehicle.
Europa Clipper is a mission to orbit around Jupiter and make multiple flyby maneuvers near Europa, an icy world that many scientists believe has a warm ocean under the ice layer. The Europa Clipper should be ready by 2024. The SLS will not be ready to launch the Europa Clipper until 2026 or later. The SLS still has several Artemis moon missions. The SLS would have to actually complete its first launch and a few other missions. There are also concerns that SLS is not compatible with aspects of the Europa Clipper.