The Object 248 was a proposed modification to the aging IS-1 with the intention of equipping it with a 100 mm gun. There were two distinct versions. The first to arrive was Object 245, armed with a D-10 cannon, followed by Object 248, armed with an S-34. They were tested in the second half of 1944. At the beginning, they were considered a failure, as the modifications did not improve the performance of the IS-1 but rather made it even worse. It was discovered that the guns were unstable and could be damaged due to weak gun cradles, and the tank commander could be hit by the breech of the gun while it was rolling back after being fired. These were not fully addressed until the end of the year, when the majority of the design flaws were corrected. Unfortunately, it was considered too late, as both German and Soviet forces had already developed more advanced tanks that outperformed both tanks, and production was promptly cancelled.

The Object 248 was introduced during Update "Danger Zone" as a reward for Battle Pass: Season VIII, "Field Testing". It has a powerful 100 mm gun that provides faster reload and more penetration at the expense of explosive mass when compared to the IS-2's 122 mm. However, because of the more than halved reload time, it can be more aggressive on the battlefield while still being able to engage enemy tanks at medium to long range, providing more versatile playstyle options.