Filtering results: Checkboxes vs dropdowns

I'm designing a filter for a website with a job search abroad. Filter has to refine vacancies displayed on the right side. I saw a lot of similar websites with job search use dropdown menus. But on my opinion options should be visible, multi selectable and easy selectable (dropdowns have accessibility problems).

What are the types of data I should use dropdowns for?

Are checkboxes good for binary data like sex, availability of accommodation (yes/no)?

Also while I'm on topic of filters is slider to regulate price good UX?