CheckBox always returns null in asp mvc

when clicking on the checkbox, form is submitted using jquery, but Checkbox always return null.

I have the following Razor Code:

@using (Html.BeginForm("Index", "HumanResource", new { type = ViewBag.CurrentType }, FormMethod.Post, new { id = "form1" }))
{
 <label class="custom-control custom-checkbox" for="Filter">
        @Html.CheckBox("Filter", new { @class = "custom-control-input" })
        <span class="custom-control-indicator"></span>
        Choose
 </label>
}

//Scipts

<script>
$('#form1 :checkbox').change(function() {
            $("#form1").submit();
   });
</script>

Controler

public async Task<ActionResult> Index(FormCollection fc,int? Filter)
{
//leftFilter is always null
}