The Source 2 engine is a significant upgrade to the Source engine which was used for older games. While Half-Life:Alyx uses Source 2 and Dota 2 has been upgraded to Source 2 with the reborn update, games like CSGO and TF2 are still stuck with the old Source engine.
THE LEAKS
The first piece of leak which shook CSGO fans came from VNN Tyler, who claimed through a video that the Source 2 port for CSGO might be coming in 2 months, but that was way back in March – add two months to that, and we’re standing right there in May.