An air carrier First Officer reported they were cleared for takeoff when the reporter observed a Cessna on short final and told the Captain to stop the aircraft.

Narrative

On the taxi out from ramp to Runway XX we were on taxiway 1 and told to follow the King Air that was also on taxiway 1 but coming from the opposite direction. There clearance was to taxi to runway XX via taxiway 2 and cross Runway XY at Taxiway 2. Following the King Air and making the turn from taxiway 1 onto 2 and just prior to crossing the hold short line for Runway XY I noticed a Cessna over the threshold landing for Runway XY. I told the Captain to stop there's a plane landing. We stopped just before the hold short line. I notified ground we're holding short for landing traffic. They then instructed us to hold short which we did. Once the Cessna the cleared the runway at taxiway 3 were given clearance to cross again. We had no further issues. When ground cleared us to cross Runway XY they never mentioned anyone on final for Runway XY. There was no runway incursion but it was very close. Ground/tower must've forgotten there was traffic landing on Runway XY as runway XX was the active. At the time there was another plane coming in to land on runway XX as well. Suggestion: For all to continue to remain vigilant in making sure runways are clear before crossing.