Drop-shotting lets players aim down sights while going into the prone position, without interrupting the line of fire. Effectively allowing them to dodge the opponents crosshair quickly, without effecting their own aim.
A new leak has revealed how a weapon attachment could be Treyarchs solution for the nerf that has been around since Black Ops 4.

Drop-shotting was included in all Call of Duty games and rewarded quick thinking players until Black Ops 4. Treyarch reduced the viability of the mechanic by forcing players into hip-fire when they transitioned to the prone position.
Treyarch have once again opted to keep this version of the mechanic essentially nerfing it in Black Ops Cold War. Although this time, there is a workaround.

The image above is how it looks when players go from standing to prone, or from prone to standing, which will ruin your shot if you make this move during a gunfight.
A bug in the Alpha for Black Ops Cold War revealed every weapons attachments, despite most of them being hidden to players. One of the attachments was called the ‘Duster Handler’ for the XM4 rifle, which lets players “aim while going prone.”
The attachment comes at the expense of Quickdraw or Impact Handle, among others, but users of the Duster Handler will be able to drop-shot with it equipped.
Based on other leaks around the internet from the BOCW Alpha, it appears as though the attachment will be available for other weapons, possibly all of them, including SMGs, Assault Rifles, and LMGs.

It looks as though Treyarch are trying to give their players the best of both worlds, allowing players who want to drop-shot the ability to while sacrificing another attachment on their guns, but stopping them from abusing it against lesser skilled opponents by removing it as a base mechanic.
Of course, we cant know if this is 100% accurate, but based on the leaked screenshots it looks to be the case, and it’s always possible that these mechanics could be changed before the final release of the game.