diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c85081dc..37fef707 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,9 +1,12 @@
 name: CI
 
-on: [push, pull_request]
+on:
+  push:
+    branches: [master]
+  pull_request:
 
 concurrency:
-  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.run_id }}
+  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
   cancel-in-progress: true
 
 jobs: