Valve previously ported Counter-Strike 2 to Source 2, and some fans would like to see a similar update for Team Fortress 2. It is possible that something like this is being prepared right now.
Well-known blogger and insider Tyler McVicker has decided to talk about TF2 this time. Dataminers have found mention in the files of a developer branch called TF, and it is assumed that this refers specifically to the online shooter Team Fortress.
Tyler highlighted new code that is associated with TF, and expressed the opinion that this is "virtually direct confirmation" that Team Fortress 2 is being ported to Source 2.
Judging by the dataminers' findings, new lines of code were added to the Source 1 import strings in October of this year, which are used to transfer content from the old engine to the newer one. Researchers discovered a mechanic characteristic of Team Fortress 2 that was being transferred to Source 2 — "func_respawnroomvisualizer."
There have been no official announcements from Valve yet, so "porting TF2 to Source 2" is still just an assumption based on some findings in the code.