To level up Hawk Eye, you need to complete specific tasks within the Hawk Watch.

To find out which tasks are required:
-Locate the Hawk Watch. Building in your city, then select "Hawk Watch."
-Tap the (Hawk Eye) icon at the bottom left of the screen.
-Check the required task types to track your progress and see what remains to be completed.

Note:
Leveling up Hawk Eye unlocks higher-quality missions in the Hawk Watch, granting you better rewards.