Status Effects
Status Effects are conditions that can have positive or negative effects on a Hero. Some range from increasing or decreasing movement speed, reducing or increasing healing received, or even being knocked into the air! Crucially debilitating status effects are referred to as Crowd Control (CC) in Soft and Hard variants. See the list below for all forms of CC and what they do in Predecessor.
Negative Status Effects
Soft Crowd Control
- Slow - Reduces player Movement Speed: Can be Cleansed, Immuned, and Mitigated.
- Blind - Cascades the player's screen in black, negating vision: Can be Cleansed, and Mitigated.
- Silence - Disables the casting of any Ability, Consumable or
Hunt, and Blink: Can be Cleansed and Mitigated.
Hard Crowd Control
- Root - Halts all player movement for the duration, while also negating usage of movement abilities and blink: Can be Cleansed, and Mitigated.
- Tethered - Locks the player's movement to the area of the Tether, disabling any and all movement abilities and blinks: Can be Cleansed, and Mitigated.
- Stun - Halts all inputs, movement, and other actions until the duration is finished: Can be Cleansed, Immuned (See Unstoppable for more info), and Mitigated.
- Knock Up - Nearly identical to a Stun, but launches the afflicted Hero a short distance into the air: Can be Cleansed, and Mitigated.
- Suppression - Functions identically to a Stun but the duration of the effect cannot be reduced in any way after it has been applied to a hero, this includes Tenacity: Can be Cleansed.
Nearly every form of Crowd Control can be completely negated through forms of Unstoppable, which is baked into a key abilities, example: 
Drongo's Shrapnel Cannon, or 
Khaimera's Invigorate. Or Through CC Immunity from item's passive effects such as 
Legacy or 
Truesilver Bracelet. Other ways of counter acting CC would be through the usage of a Cleanse. These come in a form of an often single instance active ability with a long Cooldown. Example: 
Witchstalker or 
Liberator.
Negative Debuffs
- Blight - Reduces all healing and Health Regen received by 40% while afflicted. This effect does not stack with other items that apply Blight.
- Damage Over Time (DoT) - Deals small instances of repeating damage to a player
Infernum's Cinder passive, Red Buff's Burn, and 
Grux's Bloodlust are all examples of Damage Over Time effects.
There are more hero specific Debuffs that can be found on each hero's page, such as Drongo's Rad Rounds or 
Kallari's Death Mark. Visit their pages to see each individual effect and their counter-play.
Positive Status Effects
Buffs
- Movement Speed boosts - Increases player Movement Speed by a percentage value of their base speed, can be a flat amount for a duration of time, or a decaying percentage which will slowly decrease in intensity as the status comes to an end.
- Shielding - Places a chunk of temporary Health on a Hero (Indicated by a white Health Bar segment.) Shields does not take into account the Armor of the person affected by them, therefor shred and penetration have little addition power against them. Shields can last until broken, such as the shield given by the Green River Buffs, or fall off after a certain number of seconds such as
Muriel's Consecrated Ground. Shields do not stop executions like 
Feng Mao's Ultimate, Ground Splitter. - CC Immunity - Similar to Unstoppable, CC Immunity is a buff that will grant complete Immunity to all forms of Crowd Control for the duration that it is active. Items such as Truesilver Bracelet and its passive affect Reprisal grant CC Immunity.
- Spell Shielding - Grants a single instance of Immunity to the next source of damage from an enemy. (Some Jungle Monsters can activate this effect, nullifying its possible usefulness against a powerful enemy Hero's ability.)
Mesmer and 
Spellbreaker both have passive abilities that give Spellshields. 
GRIM.exe's also has this built into their ability Energy Shield.
Psuedo-buffs
- Unstoppable - Negates all Crowd Control for a certain period of time.