Watch Dogs 2 features a robust and varied skill tree that lets you unlock a huge variety of new skills, perks and improvements. Some of the skills in the Research App are locked until you find a specific piece of Key Data. This Watch Dogs 2 Key Data Location & Research App Guide lists all of the Key Data locations with screenshots and information on how to obtain them.
You can find out if a specific skill on the Research App is locked due to lack of Key Data by navigating to the skill on your chosen skill tree. Typically they tell you if they are locked due to lacking a previous skill but they also provide information on other requirements such as locating Key Data.
Watch Dog 2 Guides
Watch Dogs 2 Side Operations Guide
Watch Dogs 2 Weapon Skins (Paint Jobs) Guide
Watch Dogs 2 Unlockable Clothing Guide – Where To Find Hidden Clothing
Watch Dogs 2 Unique Vehicles Guide – Location & Screenshots
Watch Dogs 2 Vehicle Paint Job Locations
Watch Dogs 2 Jumper Paint Job Locations
How To Earn Money Fast In Watch Dogs 2
Watch Dogs 2 Quadcopter Paint Jobs Guide
This Watch Dogs 2 Key Data Location & Research App Guide
There you have it. A complete list of every Key Data item you can find in Watch Dogs 2. Using this guide and collecting all of the items listed above will give you complete access to any ability on the skill tree.