pipeline {
    agent none

    parameters {
        string(name:'stringParam', defaultValue: null)
        run(name: 'runParam', filter: 'ALL', projectName: 'some-other-job')
    }
    
    stages {
        stage('test') {
            steps {
                echo "params.stringParam: ${params.stringParam}"
                echo "params.runParam: ${params.runParam}"
                echo "env.runParam: ${env.runParam}"
            }
        }
    }
}

Started by user unknown or anonymous
Running in Durability level: MAX_SURVIVABILITY
[Pipeline] stage
[Pipeline] { (test)
[Pipeline] echo
params.stringParam: xx
[Pipeline] echo
params.runParam: null
[Pipeline] echo
env.runParam: http://xxx/job/some-other-job/4/
[Pipeline] }
[Pipeline] // stage
[Pipeline] End of Pipeline
Finished: SUCCESS