Missions (XCOM2)

One of the big differences between XCOM and XCOM 2 are mission types. Instead of Abductions you have Guerrilla Ops, and instead of Terror Missions you have ADVENT Retaliations (losing and ADVENT Retaliation mission wont make you lose that territory, but it will decrease the supplies income).

Mission	Timer	Start Concealed	Objectives	Reward	Observations
Guerrilla ops
You can only choose one at a time. Hidden Dark Events can be revealed with Intel, either on the first popup, or by clicking the tag under the Avatar Progress counter. Choose based on what is a greater threat to you (usually the 'free +1/+2 Avatar Progress' events unless there's an easily accessible facility on the geoscape) or go by reward, or whatever mission contains a hack (only mission-critical hacks can yield the elusive "Enemy protocol" reward).
Protect Device	-	yes	Protect the device and kill all targets	Varied + Countering a Dark Event	Late game this mission might get hard due to powerful enemies attacks
Destroy Device	8	yes	Destroy the device and kill all targets	Varied + Countering a Dark Event	The ability to MC or hack control of an enemy unit makes this easier
Hack/Recover Workstation/Item	8	yes	Hack/Recover and kill all targets	Varied + Countering a Dark Event	Bring a Specialist: their ranged hack makes this significantly easier: LoS is range. Unlocking the chest/station will also give an additional bonus, like reduced scanning times, facility leads or even a permanent increase on the soldier's hacking skill.
Council missions
Secure VIP	12	no	Extract VIP and all soldiers	VIP + resources	VIP starts with you. Extraction zone is fixed and remote.
Rescue VIP	12	yes	Extract VIP and all soldiers	VIP + resources	VIP doesn´t start with your soldiers: may appear locked in a cell or an ADVENT van: bring a Specialist. Extraction zone is fixed and remote. Unlocking the door where the VIP is captive will also give an additional bonus, like reduced scanning times, facility leads or even a permanent increase on the soldier's hacking skill.
Neutralize Dark VIP	12	yes	Capture or kill Dark VIP + extract all soldiers	Supplies + Intel	If you kill the Dark VIP you don't get the Intel. On proximity, you get the 'Knockout' command, then Carry option: soldier carry rules are in effect. Extraction zone is fixed and remote.
Loot missions
Supply Raid	-	yes	Neutralize all enemies	Alloys + Elerium + Supplies	Beware of AoE attacks, don't destroy the resources: they are the glowing boxes. Keep in mind that vehicle and other object explosions have some range.
UFO Recovery	6	yes	kill all targets	Alloys + Elerium	After you break concealment a beacon will activate, you have 6 turns do deactivate it or reinforcements will be deployed.
Other
ADVENT Retaliation	-	no	save at least six civilians and kill all targets	Supplies income increased	Like in Enemy Unknown/Within; living civvies still on the map are auto-rescued once all enemies are dead. Failing to rescue 6 civilians reduces supply income. Failing to secure the area loses the territory entirely.
ADVENT Facility	-	yes	Plant the X4 and evacuate	AVATAR progress decreased by point amount displayed under facility on map	Expect drops either once enemies are dead, when the charges are set, or on your way to extraction.
Avenger Defense	-	yes	Destroy the Disruptor, don't let enemies inside the ramp	Not losing the game	Defense Matrix helps a lot to camp the ramp, upgrade if you can. MCing and/or Hacking is VERY useful: have the controlled enemy unit take out the Disruptor, while your soldiers retreat, as ADVENT will be airdropping new enemies first every other turn, then eventually every turn.

In addition there are several special one-off storyline missions.