It has become extremley infamous for the combination of Danger Close and the Grenade Launcher, as it makes the already powerful grenades become overpowered. Many players have stopped playing the game and left because of this.
Danger Close returns in Call of Duty: Ghosts. It increases explosive damage by 40%. This effect is much more prominent on Grenade Launchers, including the underbarrel attachment, the Kastet, and the MK32. The Kastet has the most notable increase in damage due to its already large blast radius. This, when paired with Recon, can help with tagging enemies holding up in rooms/areas. Danger Close also applies to killstreak explosives, but it is most noticeable on the Gryphon.
Danger Close returns again in Call of Duty: Advanced Warfare. The perk increases explosive and scorestreak damage. Danger Close is best used in conjunction with Grenade Launchers, increasing the overall effectiveness of all launchers. Due to the introduction of the Exo Suit, enemies have a chance to boost jump or dash to the side away from fired explosives if the player alerts them before shooting, allowing enemies to survive the impact of the explosive and get out of the way of the blast radius. Equipping Danger Close increases the potential of a one shot kill, or, if the player misses, the increased damage can harm enemies greatly, making a follow up shot with a different weapon kill much quicker.
Enemies equipped with Exo Trophy System can deflect up to 2 explosives. Players should avoid using the Underbarrel Grenade Launcher against these types of enemies, as the attachment fires too slow, causing the player to be potentially killed while reloading. Grenade Launchers like the MDL should be used as the magazine size allows for rapid firing, which can easily bring down enemies with the Exo Ability.