The Strife can be found from the wall or from the Mystery Box or can be equipped as a starting weapon. When upgraded via Pack-a-Punch Machine, it becomes the Z-Harmony, where it becomes fully automatic, has its magazine size increased to 30 rounds (49 with Extended Mags) and its ammo reserve increased to 270.
The Strife in first person
Aiming down the sights
Pre-Alpha menu icon
Pre-alpha HUD icon.
Z-Harmony customized in third person
Z-Harmony with stiletto knife, extended mag, long barrel, and quickdraw grip coming out of the PAP Altar
Interestingly, this makes the Strife's appearance in Cold War an in-universe anachronism - the Strife would be created in the Black Ops timeline somewhere between 2025 (Black Ops II) and 2045 (Black Ops 4), while the two maps are set in 1981 (Operation Red Circus) and 1983 (Crossroads).