Not built in, but PowerShell 7 adds a Parent property to every process object (a CodeProperty on System.Diagnostics.Process), so a tree is a few lines away. Building the parent→children map once keeps it fast:

function Show-ProcessTree {
    param([int]$RootId = 0)
    $procs = Get-Process
    $byId = @{}; foreach ($p in $procs) { $byId[$p.Id] = $p }
    $children = @{}
    foreach ($p in $procs) {
        $parentId = if ($p.Parent -and $byId.ContainsKey($p.Parent.Id)) { $p.Parent.Id } else { 0 }
        if (-not $children.ContainsKey($parentId)) { $children[$parentId] = [System.Collections.Generic.List[object]]::new() }
        $children[$parentId].Add($p)
    }
    function Write-Node($id, $indent) {
        foreach ($c in ($children[$id] | Sort-Object ProcessName)) {
            '{0}{1} ({2})' -f $indent, $c.ProcessName, $c.Id
            if ($children.ContainsKey($c.Id)) { Write-Node $c.Id ($indent + '  ') }
        }
    }
    Write-Node $RootId ''
}

Show-ProcessTree                                        # whole tree
Show-ProcessTree -RootId (Get-Process -Id $PID).Parent.Id   # just one branch

Sample output (PowerShell 7.4.6 on Ubuntu 24.04):

systemd (1)
  agetty (184)
  bash (936)
    sleep (8249)
  cron (157)
  dbus-daemon (158)

Processes whose parent has already exited (or isn't visible to you) are shown at the top level, which is also how pstree behaves. If you need more columns, emit objects with a Depth property instead of strings and pipe them to Format-Table.

Nothing built in, but you can create a function (like the nice example from Marcus de Paula (@marcuspaula-seceng)). You can also try the Show-ObjectTree command from the Microsoft.PowerShell.ConsoleGuiTools module, which includes a TUI.

Install-PSResource -Name 'Microsoft.PowerShell.ConsoleGuiTools'
Get-Process | Show-ObjectTree
Get-Process -Name 'msedge' | Show-ObjectTree

Mr Beedell, Roke Julian Lockhart (@beedell-roke) - this has been in discussion in the Cmdlets Working Group where I have been looking at adding a Parent Parameter to Get-Process. & I've even debated whether or not a [-Children] parameter is needed too.

That is needed as a first step before we could look at returning a full Process Tree, which we've been debating about how this should be, like is it a default view that we display when you run -Parent, should we have a -AsTree additional parameter, should it even be a completely separate Format-Tree cmdlet that's generic that we can then use for this usecase.

I'd like an end goal to be similar to what is shown by Marcus de Paula (@marcuspaula-seceng) using that property except that we'd continue to return the objects with the properties that are shown today & crucially still allow people to make use of the pipeline.

Please add examples of how you'd like this to work into that linked issue & importantly any suggestions on how it should display too so that we can consider it, but yes this is something that I'd like to have be part of the Get-Process cmdlet.

There is a Module on the Gallery that implements a Get-ProcessTree function but it doesn't meet my strict needs or potential desired output here.

My view is thst Get-Process should only ever get processes. It gets processes for use in automation, including making pretty output.
If you want a nice tree, or any other human readable format, create Format-Process cmdlet, and put it into the gallery.