PowerShell 5.1
Invoke-Command -ScriptBlock {start-job {gsv}} -ComputerName Will
Invoke-Command -ScriptBlock {get-job} -ComputerName Will
Nothing was displayed. I couldn't retrieve any job.
Jobs are tied to the current session. The way you run Invoke-Command creates a new session with every invocation, so the second session naturally doesn't know anything about jobs of the first one.
Change your code to something like this, so both invocations run in the same session:
$session = New-PSSession -ComputerName Will
Invoke-Command -Session $session -ScriptBlock { Start-Job {gsv} }
Invoke-Command -Session $session -ScriptBlock { Get-Job }
Remove-PSSession $session