They wouldn't want to give up valuable strategic locations and important industrial facilities without something really juicy in return. I would imagine being a 100% equal joint-partner in advanced technology programs would be one, and large economic concessions at the very least. Germany would become highly reliant on Soviet manufactured goods and raw resources as the war went on.
This would also lead to a much earlier and better focus on air-defense for the USSR, since they weren't really in range of Allied bombers until late war, and they would recognize the need for high altitude interceptors and big AA guns sooner.
They would probably license-build german radars, which were very good.
Also the 130mm AA gun sees service far earlier.
Air-defense would get a boost, they'd probably get better high-altitude superchargers.
The soviets had designed and started to build world class aircraft by 1940, Pe-2s, Tu-2s, IL-2s, IL-4 and Pe-8s, for air superiority you had the Yak-1s, LaGGs which could be better designed and tested before becoming the flying coffins they became famous for, and for the PVO, the mig-3 would shine in its role as a high altitude fighter, especially if it gets a 2nd stage supercharger and gets the MG-151, Problem was a total lack of organization and pilots, even spare parts for all this.
Which again would be remedied by no Barbarossa.
No escorts until 1942-43, unless this TL fixes the P-38's teething problems earlier.
Vladivostok and Murmansk would be immune to air attack, you'd need to fly thousands of miles, with hundreds of miles unescorted across enemy territory.