Killstreaks
Call of Duty Modern Warfare Remastered has the same three killstreaks as the original. They become available when a player obtains three, five, and seven kills within the same life. Any sort of kills will count towards the killstreak. For example, if you have two kills with a gun, one kill with a knife, one kill with an explosive, call in an airstrike and get two more kills with that airstrike, you will immediately get an attack helicopter. Be aware, if you get one kill streak without using it and obtain the next kill streak, you will lose the ability to use the previous kill streak.
UAV
UAV is short for Unmanned Aerial Vehicle. This killstreak becomes available after scoring three kills within the same life. It will show all players on the mini map for 30 seconds. Only players with the UAV Jammer Perk 2 will not show up on the mini map. This is highly useful for elimination games like search and destroy or team deathmatch.
Airstrike
The Airstrike becomes available after scoring five kills within the same life. This killstreak allows you to mark a location on the map that will be hit by three airstrikes in a row. It can also kill you, so make sure it’s not dropped right above you. Pair the airstrike with UAV to find the best kill zone.
The only way to counter an airstrike is to rush to safety. Hide within a building or underground to survive.
Attack Helicopter
The Attack Helicopter becomes available after scoring seven kills within the same life. This killstreak calls in an AI-controlled helicopter that will fly around the map for 60 seconds. The helicopter will shoot at enemy players with its machine gun and rockets.
The best way to counter the attack helicopter is to stay in doors or to shoot it down. Light Machine Guns and RPGs are the fastest way to take down attack helicopters.
A trick veteran players use is to wait until they die to call in the Attack Helicopter. All kills made by the helicopter in the next life will count towards the next killstreak. However, if you die again, the kills by the helicopter will not count towards the next killstreak.