Which command would tell you if a Falcon Sensor was running on a Windows host?

The command that would tell you if a Falcon Sensor was running on a Windows host is sc.exe query csagent. This command will show the status of the csagent service, which is responsible for running the sensor on Windows systems. The output of this command will indicate if the service is running, stopped, or paused. If the service is running, the sensor is also running3.

References: 3: How to Become a CrowdStrike Certified Falcon Administrator