The queue orb was previously used to avoid multiple pipeline race conditions and conflicts. Serial-job provides native support for the functionality provided by the queue orb. Overtime we will expand the use cases we support to cover additional challenges like multi-job or workflows. The first release is serial-group for individual jobs.
This allows an individual job to be serialized across the organization, project or branch based on the parameters you provide. Serialization will ensure the jobs are executed in the order in which the pipelines are started via commit, api or other triggering method.
To learn more about your options see the documentation.