Frontline workers are individuals who provide direct services to the public or perform hands-on duties essential to an organization's operations. They typically cannot work remotely and must be physically present to do their jobs.
Use frontline (one word) as an adjective (e.g., "frontline worker") and front line (two words) as a noun (e.g., "they were on the front lines"). 📺 2. FRONTLINE (PBS Documentary Series)
While "essential" workers maintain critical infrastructure (like a remote IT analyst at a utility company), "frontline" workers specifically face the public.