+2 to Charisma and +2 to your Choice of Strength, Dexterity or Constitution.

You mature and reach adulthood the same time as your mortal parent. You then can live for multiple centuries or you can possibly be immortal.

Cambions have an innate tenancy towards evil and sin due to their fiendish blood, thus a majority have an evil alignment. Depending on the type of fiend they may lean strongly towards chaos or law. However some have bested their nature and may be neutral aligned even in some rarer cases good aligned.

Due to your fiend blood you can see in the dark and in dim conditions. You can see in dim light within 60 of you as if it were bright light, and in darkness as if it were dim light. You can't discern color in darkness, only shades of gray.

Choose a proficiency in 1 of the following skills.

Persuasion, Deception, Intimidation, Performance, Insight 

You can choose to be resistant to two of the damage types listed here, and another resistance at 5th level:

Fire, Lightning, Cold, Poison, Acid

Or you can choose to instead gain the benefit of Adding your Charisma Modifier to your Armour class (AC) and your choice of 1 resistance from the list above. This can be added along with your Dexterity Modifier. however you can only Add a +2 if you are wearing Medium or Heavy Armour. Feats such as Heavy Armour master and Medium Armour master boost this to a +3.

However you loose the benefit of this trait if you are hit with Radiant damage or a Silvered weapon, until you take a short or long rest.

Your blood has given you access to infernal magic that you can call upon at will.

At 1st level you can choose 1 of the following cantrips:

Thaumaturgy, Firebolt, Chill Touch, Eldritch blast, Friends, Minor Illusion, Produce Flame, Green Flame Blade.

At 3rd level choose 1 of the following spells casting it once, to do so again you need to take a long rest.

Burning Hands, Charm Person, Bane, Inflict Wounds, Command, Searing Smite, Wrathful Smite, Disguise Self, Detect Magic, False Life, Grease, Ray of Sickness, Tasha's Hideous Laughter, Arms of Hadar, Hex, Armour of Agthys (2nd level), Hellish Rebuke (2nd level), Witch Bolt.

At 5th level choose 1 of the following spells casting it once, to do so again you need to take a long rest.

Blindness/Deafness, Hold Person, Continual Flame, Flame Blade, Flaming Sphere, Branding Smite, Alter Self, Darkness, Suggestion, Scorching Ray, Ray of Enfeeblement, Crown of Madness.

Charisma is your spellcasting ability for these spells.

By expending a use of 1 of your racial spells

Your next illusion or Enchantment spell lasts twice as long. 

Or: 

When you roll a 1 on a damage die for a spell or attack it is treated as a 2, for the next hour if the 3rd level racial spell was used or for 3 if a 5th level racial spell was used.

To do this during combat costs a bonus action.

If you are hit with radiant damage silvered weapon you loose this if it is in effect and cannot use it until a short or long rest.

For all intents and purposes your creature type is fiend not humanoid.

As a fiend you also have some unfortunate unique weaknesses.You have vulnerability to Radiant damage and Silvered weapons.

Also if an NPC or PC is aware of your Fiendish nature all charisma checks are made at disadvantage (DM's discretion) apart from intimidation checks. 

You can speak, read and write Common, Infernal and Abyssal