Most people think clearing cookies resets their trail. It doesn't. Cookies are one identifier among dozens, and they are the easiest one to remove. The rest of what identifies you sits deeper, and most of it survives a cookie wipe untouched.
Here is what your browser exposes to every site you visit, before you log into anything. Your screen resolution and colour depth. Your timezone. The fonts installed on your system. Your GPU, through the way it renders graphics. Your browser's canvas output, a small image the page draws and reads back, which varies by hardware and software in ways precise enough to identify a machine. Your WebGL profile. Your language and locale settings. Individually, none of these names you. Combined, they form a pattern stable enough to recognise you across sessions, across sites, and after every cookie you own is gone.
This is a browser fingerprint. It is passive, it needs no cookie, and it works in a fresh private window.
Why it matters if you run more than one profile
For most browsing, a fingerprint is a privacy footnote. It matters the moment you keep separate browsing contexts on purpose. An agency running client accounts. A researcher keeping investigations apart. Anyone holding work and personal browsing at arm's length. If those contexts share one browser on one machine, they share one fingerprint, and the thing keeping them separate in your head is not keeping them separate to the sites reading them.
Clearing cookies between sessions does nothing here. The fingerprint is the same before and after.
What actually separates them
Real separation means each context running in its own isolated environment: its own storage, its own network path, its own consistent locale and timezone. Not one browser wearing different hats. Distinct environments that never share state.
Chameleon Hive does this by running each profile in a real, unmodified browser with its own isolated container around it. The browser stays authentic; the isolation lives in the environment. That's the architecture, explained in full on the how it works page.
The short version
Cookies are the visible layer and the easy one to clear. The fingerprint underneath is more stable and survives the wipe. If separation matters to your work, isolate the whole environment, not just the cookie jar.