Add this line to your app's build.gradle inside the dependencies section:
implementation 'com.mercadolibre.android:cardform:2.+'
With this command you can generate a local version for testing:
./gradlew publishLocal
CardForm.Builder.withAccessToken("user_access_token", "current_site_id", "integration_flow_id").build()
.start("activity_from", "request_code")