Zenodo is general-purpose repository that hosts mixed resource types (articles, data, software, posters, presentations etc). Google Scholar only indexes text content (articles) and thus other resource types in Zenodo is out of scope for Google Scholar. Google Scholar relies on patterns in the URL to determine the resource type (e.g. /articles/1234 vs /data/1234). Zenodo's allows users to edit and change the resource type after publishing, which would mean the URL of records in Zenodo would change if you edited the resource type. Implementing this behaviour would be against best practices for digital repositories and against our commitment to provide stable links to records. Google Scholar are therefore not indexing Zenodo. We have met with Google over the years to find a solution, but so far there is no resolution.
Note, that Google Dataset Search does index Zenodo, as Dataset Search relies on embedded schema.org metadata in the record landing to determine the resource type. Similarly, Zenodo is also indexed by Google Search.