If settings appear correct but still won't work, a bugged session often needs a manual refresh.
Go to Settings > Audio > Voice Chat and ensure "Proximity Chat" is toggled On . Fix Warzone 2.0 Proximity Voice Chat Not Working
Open the tab (the headset icon) while in the lobby or match. If settings appear correct but still won't work,
Proximity Voice Chat is a defining feature of the Warzone 2.0 experience, but it frequently glitches out due to misconfigured channels or bugged toggles. If you can’t hear nearby enemies or they can’t hear you, follow these steps to restore the audio. Proximity Voice Chat is a defining feature of the Warzone 2
The most common cause is the setting simply being disabled or restricted to your immediate squad.
Locate the Game Voice Channel setting. If it is set to "Party Only" or "Friends Only," proximity chat will not function. Change this to "All Lobby" to communicate with everyone in range.