Apply Query Filter for Getting List Items using CSOM with PowerShell on any SharePoint Platform

Add-Type -Path "C:\Program Files\Common Files\microsoft shared\Web Server Extensions\15\ISAPI\Microsoft.SharePoint.Client.dll"
Add-Type -Path "C:\Program Files\Common Files\microsoft shared\Web Server Extensions\15\ISAPI\Microsoft.SharePoint.Client.Runtime.dll"

$siteURL = ""

$userId = ""  #Not required for on premise site
$pwd = Read-Host -Prompt "Enter password" -AsSecureString  #Not required for on premise site
$creds = New-Object Microsoft.SharePoint.Client.SharePointOnlineCredentials($userId, $pwd)  #Not required for on premise site
$ctx = New-Object Microsoft.SharePoint.Client.ClientContext($siteURL)
$ctx.credentials = $creds #Not required for on premise site
try{

    $lists = $ctx.web.Lists
    $list = $lists.GetByTitle("TestList")
    $query = New-Object Microsoft.SharePoint.Client.CamlQuery
    $query.ViewXml = "<View><Query><Where><Eq><FieldRef Name='Title' /><Value Type='Text'>b</Value></Eq></Where></Query></View>"
    $listItems = $list.GetItems($query)
    $ctx.load($listItems)
    $ctx.executeQuery()
    Write-Host " " $listItems.Count " Item(s) Found"
    foreach($listItem in $listItems)
    {
        Write-Host "ID - " $listItem["ID"] "Title - " $listItem["Title"]
    }
}
catch{
    write-host "$($_.Exception.Message)" -foregroundcolor red
}