In a GCCH tenant is it possible for a person who has a delegation on another Inbox and Calendar to surface the content with Copilot

In a GCCH tenant, Copilot can be used with delegate and shared mailboxes and calendars, but Microsoft 365 Copilot Search is not available in GCCH, which limits some of the “surface content with Copilot Search” scenarios that work in commercial.

From the context:

• Copilot in Outlook is available in GCCH (with some limitations), so delegate scenarios that rely on Outlook’s built‑in Copilot experiences (for example, drafting or summarizing emails where the delegate has access) are supported.
• The Microsoft 365 Copilot app and Copilot Chat are available in GCCH, but Microsoft 365 Copilot Search is explicitly listed as “Not currently available” in GCCH. That means GCCH users cannot use Copilot Search to query across Microsoft 365 data (including delegated mailboxes/calendars) in the same way as in commercial.
• The documentation for using Copilot with shared and delegate mailboxes and calendars does not list GCCH‑specific exceptions, but those capabilities depend on the underlying Copilot features (Outlook, Copilot app, Search). Where those features are unavailable or limited in GCCH, the corresponding delegate scenarios are also limited.

Regarding ETA/roadmap: the context only states that the feature availability table reflects the status “as of the last update date” and points to the public Microsoft 365 Roadmap for launch timelines. No specific ETA or roadmap entry for enabling Microsoft 365 Copilot Search (or delegate search parity) in GCCH is provided in the context.

So, today:

• Delegate access plus Copilot in Outlook and the Microsoft 365 Copilot app is supported in GCCH within the limits of those products.
• Copilot Search–based experiences (like the full Microsoft 365 Copilot Search across tenant data, including delegated content) are not available in GCCH.
• No ETA or roadmap details for GCCH parity are available in the provided material; the Microsoft 365 Roadmap must be consulted for up‑to‑date plans.

References:

• Use Copilot in shared mailboxes and delegate mailboxes
• Use Copilot search in calendar items as a delegate
• Microsoft 365 Copilot