https://www.gamespot.com/articles/ghost-recon-wildlands-update-featuring-rainbow-six/1100-6460696/

The stylized military action worlds of the Tom Clancy brand are colliding, as a special event in Ghost Recon Wildlands brings in characters from Rainbow Six Siege. You can use two new Siege-inspired PvP classes or complete a two-part PvE mission starring Siege's operators.

In the mission from Special Operation 2, titled Operation Archangel, Valkyrie tracks the missing operator Caveira to Bolivia. You'll partner with Twitch to help Valkyrie find Caveira, while unlocking the mystery of why he's in Bolivia at all. You can start the mission in the province of Caimanes, and it can be taken on solo or with four-player co-op.