Google’s next flagship Pro-level model has been delayed multiple times, with Gemini 3.5 Pro ultimately canceled after repeated slips past June and July 2026 targets due to benchmark shortfalls and reliability issues. Instead, the company pivoted to Gemini 4 Argon, announced September 30 with limited rollout to select cybersecurity partners via the Fairwind Program for safety evaluations. This larger frontier model targets complex coding, long-horizon reasoning, and professional workloads, outperforming prior Pro versions on several benchmarks while trailing rivals on others. Post-training continues with no public availability date confirmed, though internal testing and phased access signal potential broader release by year-end amid competitive pressure from OpenAI and Anthropic. Traders should monitor official Google DeepMind updates and any expansion beyond gated access.