Sig Sauer just announced the new P320 AXG-Legion 9mm handgun today. This is similar to the treatment that the P365 X-Macro received, but in a P320 chassis. It will have a Legion Gray finish, magwell, 2-port comp integrated into the slide, and (3) 21-round magazines.
Like all P320s with a magwell your magazine options are limited to Legion 17rd magazines, 21rd extended magazines (included), or the 30rd extended magazines. Standard flush fit fullsize 17rd magazines will not work with the magwell installed. Overall this is a welcome addition to the P320 line and it's nice to see more variations and options after so many models were cut in the last few years due to supply constrictions.