A new and indipendent Italian faction would intrigue the players since Italian faction are rarely seen in strategic games. There are room for more microtransaction of specific Battlegroups for this Italian faction.
COH experienced players already know the capabilities of many Germans variations alternatives. After CoH1 and CoH2, we are really consumed on playing Germans as only Axis force. We hope for the Italian / African setting just for an opportunity to play an Axis faction that's not going to be Germany.
An Italian faction would bring a complete refreshing vibe to the game with it’s never seen vehicles, playstyle and armament, and the Italian fight alongside the two belligerents after 1943 could present great evolution for the playing game. We can have (like it was in the real history) two Italian factions one with the Allies and one with the Axis.
Ideas for Relics: immediately after the Allied invasion of Italy in September 1943, the Italian government switched sides. The German occupying forces ruthlessly disarmed the Royal Italian Army and from then until the end of the war Italian troops fought on both sides: with the forces of the 'Salo Republic' allied with the Germans, in the Allied 'Co-Belligerent Forces'. This period of bitter struggle saw the appearance of many new Italians units and a wide range of interesting uniforms. Accordingly, you can create two Italian factions as you wish:
1. Italian Axis Faction “Italian Republican Units”.

Faction link to the northern Italian territory mostly equipped with Italian aggressive light and rescued medium vehicle (with some German equipment) with streamlined units which can be used both defensively or offensively.
Naval infantry battlegroup
Alpine infantry battlegroup
Rescued vehicles infantry battlegroup

2. Italian Allies Fraction “Italian Co-Belligerent Forces”.

Faction link with the allies mostly equipped with allies’ vehicles and equipment with flexible infantry, light vehicles, and few share of tanks but with main capabilities in support and logistic helping them specialize to more efficiently deal with the battle ahead.
Support and logistic battlegroup;
Engineer and infrastructure battlegroup;
Meccanized Infantry battlegroup.

“Italian Republican Units” requirements.
OKW should have equipped, armed and trained four Italian divisions (one alpine and three infantry) for a total of 52,000 men. The production of medium and heavy tanks restarted, with a total of 24 Carri Armati M15/42 medium tanks and about 100 Carri Armati P26/40 heavy tanks produced until early 1945. In Anzio (January to June 1944), some Xª Divisione MAS battalions with some SPA-Viberti AS42 and some paratrooper units took part. In the Gothic Line Offensive (August 1944 to March 1945), only the Armata Liguria was deployed with the 1ª Divisione Bersaglieri ‘Italia’, the 3ª Divisione Fanteria di Marina ‘San Marco’, and the 4ª Divisione Alpina ‘Monterosa’ of the RSI, which were trained in Germany by German instructors. On the rearguard and right wing of the defensive line, the Legione “M”, the Battaglione ‘Mameli’ of the 8º Reggimento Bersaglieri ‘Manara’ were deployed. From December 1944, the Battaglione ‘Lupo’ of the Xª Divisione MAS was also deployed. All these units had fewer than a dozen tanks and armored cars each. In addition, a famous large offensive operation against the Allies was a regimental-size tactical counterattack in the Appennines in the Winter of 1944 against Brazilian troops. The operation was a success, and the Italian Republican Units proved themselves very skilled and aggressive in this otherwise brief encounter.

“Italian Co-Belligerent Forces” Requirements.
The Italian Co-belligerent Army was composed by various division sets of the former Royal Italian Army during the period when it fought alongside the Allies during World War II from October 1943 onwards. The Italian Co-belligerent Army fielded between 266,000 and 326,000 troops in the Italian Campaign, of whom 99,000 were combat troops and between 150,000 and 190,000 were auxiliary and support troops, along with 66,000 personnel involved with traffic control and infrastructure defence. On the whole, the Italian Co-Belligerent Army made up 1/8 of the fighting force and 1/4 of the entire force of 15th Army Group of the Allied Forces.
Expecting to see units of different nationalities, Company of Heroes 3's faction roster should be the most varied we've seen from a game in the series at launch, this day and age is the Axis turn to evolve.