tra_backend/hr_resignation/views/hr_employee.xml

<?xml version="1.0" encoding="UTF-8"?>
<odoo>
    <record model="ir.ui.view" id="hr_employee_resign_form_view">
        <field name="name">hr.employee.form.view</field>
        <field name="model">hr.employee</field>
        <field name="inherit_id" ref="hr.view_employee_form"/>
        <field name="arch" type="xml">
            <field name="joining_date" position="after">
                <field name="resign_date" attrs="{'invisible': [('active', '!=', False)]}"/>
            </field>
        </field>
    </record>

        <record model="ir.ui.view" id="hr_employee_resigned_filter">
        <field name="name">hr.employee.form.filter</field>
        <field name="model">hr.employee</field>
        <field name="inherit_id" ref="hr.view_employee_filter"/>
        <field name="arch" type="xml">
            <field name="job_id" position="after">
                <filter string="Resigned Employees" name="resigned" domain="['&amp;',('resigned', '=', True),('active', '=', False)]"/>
                <filter string="Fired Employees" name="fired" domain="['&amp;',('fired', '=', True),('active', '=', False)]"/>
            </field>
        </field>
    </record>
</odoo>