The Replacer was released on March 19th, 2019 as part of the "Replacer Bundle" in the Black Market for 1100 CODPoints. A variant of the character, called "The Liquidator" was released on July 23rd, 2019 as a Special Order in the Black Market for 1000 COD Points.
The "Replacer Bundle"
"The Liquidator" Special Order
The Swordfish MKII that comes with the Replacer Bundle features a cycling list of jobs the Replacer has "replaced" for, such as jobs like the President of the United States and an astronaut.