The new `background: true` keyword runs a step asynchronously and moves immediately to the next one. Two companion keywords control synchronization: `wait` blocks until specific named background steps finish, and `wait-all` blocks until every prior background step is done. It's a cleaner model than the long-standing workaround of splitting work across jobs just to get parallelism. The practical win is real — pipelines with independent setup tasks (seeding a cache, spinning up a service, running a linter) can now overlap those steps in a single job rather than paying the overhead of separate job coordination. Whether it's worth the cognitive load of explicit `wait` calls depends on your workflow's topology, but for pipelines that already feel like they're fighting the sequential-steps constraint, this is the right fix.