GetExploitantInput.cs

public class GetExploitantInput
{
    public int? IdIe { get; set; }
    public string ExploitantNummer { get; set; }
}

GetExploitantInputType.cs

public class GetExploitantInputType : InputObjectType<GetExploitantInput>
{
    protected override void Configure(IInputObjectTypeDescriptor<GetExploitantInput> descriptor)
    {
        descriptor.OneOf();
    }
}