Checking the cron's running

We'd expect to see the service is in the active (running) state:

$ sudo systemctl status cron.service
● cron.service - Regular background program processing daemon
   Loaded: loaded (/lib/systemd/system/cron.service; enabled; vendor preset: enabled)
   Active: active (running) since Thu 2019-08-22 14:58:40 UTC; 2 weeks 4 days ago
     Docs: man:cron(8)
 Main PID: 83835 (cron)
    Tasks: 1 (limit: 2225)
   CGroup: /system.slice/cron.service
           └─83835 /usr/sbin/cron -f