It appears that STALKER 2, formerly subtitled ‘Heart of Chernobyl’, will now be called STALKER 2: Heart of Chornobyl, adopting the Ukrainian spelling of the game’s principal setting. While the devs have not made a formal announcement of a title change, all references to the location on the game’s Steam page have now been updated (via ResetEra) to the ‘Chornobyl’ spelling. (The Xbox page is currently unchanged.)
Long-standing English transliterations of many Ukrainian location names are derived from Russian, not Ukrainian. In 2018, the Ukrainian Ministry of Foreign Affairs started a campaign called KyivNotKiev, encouraging international media to use spellings derived from Ukrainian for locations like Kyiv.
STALKER 2 developer GSC Game World is based in Ukraine, and the studio has recently been using its social media channels to ask fans to support Ukraine during the ongoing Russian invasion. GSC Game World points fans to a special account for the Armed Forces of Ukraine, or the international charitable foundation Come Back Alive.