|We don't know which examples you've been looking at. But the whole point of thread-local storage is that it's local to the thread; one thread cannot modify a TLS variable for another thread. (At least not without jumping through several flaming hoops whilst drenched in LPG and holding a large firework.)
Each thread gets its own copy of the TLS variable. If thread A set it to 5, and thread B sets it to 6, thread A will still see it set to 5.
Thread Local Storage | Microsoft Learn[^]
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