You can link a PR to a Linear ticket by using a magic word and the ticket number in the PR description E.g. Fixes MOD-124
List of magic words: lose, closes, closed, closing fix, fixes, fixed, fixing, resolve, resolves, resolved, resolving, complete, completes, completed, completing
This is handy when you have made a PR that doesn’t have the ticket id in th branch name / title so Linear didn’t automatically link it. (e.g. when you have a ticket for a bug and the fix is a revert of a previous PR, or a PR that fixes multiple tickets.)