I am going to give you facts about each game series so you can decide which one you’d like to play the most.
First off, Call of Duty has focused aim, extended clip (a perk), perks, you are able to create a class of guns/weapons, you can be a drone also.
But Halo has alien, energy swords, over half of the games are about one man, alien guns, and it has alien invasions too.
But they both have things in common; automatic machine guns and sniper rifles, first person
shooters, and both soldiers.