https://twitter.com/cslegacygame/status/1940474749441732869
https://archive.ph/Yr2F1

Despite following the terms and conditions provided by Valve for use of the Source SDK (https://archive.ph/KOwpo), Valve has chosen that CS Legacy is forbidden to use the Counter-Strike IP in their modification.

It would appear that Valve is afraid of the community out doing them on an IP they took from the community in the first place. Sad!
CS:Legacy (@CSLegacyGame) on X

CS:Legacy Project Status Update

X (formerly Twitter)
@Theuaredead I guess it's time for fans to create an independent IP away from CS while using it to make their own fan works... 
@pixelreality That appears to be the course that CS Legacy will take if they don't resolve the issue with Valve. Now, the real question is whether they'll survive the migration.