In

Filter::field('name', [FilterType::IN]);

$filter = [
    'type'   => '$in',
    'target' => 'name',
    'value'  => ['Taylor', 'Otwell',]
];

$sql = Person::filter([$filter])->toRawSql();

select * from "people" where "people"."name" in ('Taylor', 'Otwell')

select *
from "people"
where (
    "people"."name" in ('Taylor', 'Otwell')
        or
    "people"."name" is null
)