Check the field value in Twig Drupal 9

{% if 'some field value' in entity.field_name[0] %} //Output the result that we need
 {% else %}
//Output the result if the validation of the value is not successful
 {% endif %}

Where:

• entity - entity type
• field_name - machine name of the field we need

Example:

{% if 'In stock' in product.field_stock[0] %}
{{ product.field_stock }}
{% else %} { product.field_stock }} 
{% endif %}