Three years ago, the team that built LGTM.com joined GitHub. From that moment
on, we have worked tirelessly to natively integrate its underlying CodeQL
analysis technology into GitHub. In 2020, GitHub code scanning was launched in
public beta, and later that year it became generally available for everyone.
GitHub code scanning is powered by the very same analysis engine: CodeQL.
We’ve since continued to invest in CodeQL and GitHub code scanning. Today,
GitHub code scanning has all of LGTM.com’s key features—and more! The time has
therefore come to announce the plan for the gradual deprecation of LGTM.com.
lgtm.com is now part of Github code scanning.
The following quote is taken from The next step for LGTM.com: GitHub code scanning!.