There are a total of 8 Talents for each section (Medical, Tech, Security). Talents are unlocked via a Base of Operations upgrade and can be assigned to 1 of 4 talent slots. Only 1 slot is available initially. The others are unlocked as you rank up.
Adrenaline
Shock and Awe
Critical Save
Combat Medic
Strike Back
Shrapnel
Battle Buddy
Triage
Tactical Advance
Police Up
Evasive Action
Wildfire
Death by Proxy
Tech Support
Fear Tactics
Demolition Expert
Steady Hands
Precision
Desperate Times
Repo Reaper
One is None
Stopping Power
Chain Reaction
On the Move