If you suspect your credentials might be in such a list, security experts from Norton and Avast recommend the following:
The specific file you mentioned, "1,5M COMBOLIST GMAIL (TARGETED GAMING).txt," indicates a curated collection of 1.5 million Gmail accounts specifically gathered because of their association with gaming platforms (e.g., Steam, Epic Games, or PlayStation). What this file is used for 1,5M COMBOLIST GMAIL (TARGERED GAMING).txt
If a service notifies you of a breach, change your password to something unique and strong. Do not reuse this password on other sites. If you suspect your credentials might be in
Use a tool like Have I Been Pwned to see if your email has appeared in any recent breaches. 5M COMBOLIST GMAIL (TARGETED GAMING).txt