German Doctrines or Soviet Tactics, or Allied Companies, are selectable different sets of abilities available in Skirmishes, Online Play, and Theater of War Scenarios in Company of Heroes 2.
In previous Company of Heroes Games, Command Trees were available to Commanders, which offered passive abilities and benefits for a specific strategy towards winning the game. The way these abilities would be reached is by earning Command Points to purchase them.
Doctrines, unlike Tech Trees from other Company of Heroes games, are less a straight way to win the game and more an enhancement to existing forces (Although there are some Doctrines that make defending easier, or attacking, or making a focus on anti infantry or anti tank roles.) There are Passive Abilities that (for instance) may allow your Conscript Squads to requisition PTRS-41 anti tank rifles for better use against enemy vehicles, or Rechargeable Abilities that may allow you to call in en Elefant heavy tank destroyer.