Starting with macOS 10.13.0 (High Sierra), Apple created a whitelist for KEXTS. This is a new Apple feature that requires user approval before loading new third-party kernel extensions such as Cb Defense kernel extension, com.confer.sensor.kext for Sensor version 3.0 or com.carbonblack.defense.kext for Sensor version 3.1 or higher. See Apple Technical Note TN2459 for more details and recommendations for enterprise environments.
In some situations you may see an additional pop up stating that a reboot is required; however, the sensor does not need to reboot after the install/upgrade on physical machines. You may choose not to reboot and the sensor should reload within 30 minutes.