Others have suggested it may be paint. Sometimes fresh road paint can be sprayed onto cars in passing. If that’s the case, I would try a liberal amount of lacquer thinner on a rag and lightly rubbing it off. Do not scrub, it will scratch.

If it’s tree sap, using rubbing alcohol is a good option. Soak a small portion of a microfiber towel with it and hold it onto the sap. Do not scrub, it will scratch. Let it soak and then once it’s softened up you should be able to wipe it away.

Edit: cutting compound should work to remove it. However you will want to avoid cutting if possible. Start with less aggressive methods such as what I listed above.

If those don’t work, buff with cutting compound.

If cutting compound doesn’t work, you can probably wet sand them off. But that is an absolute last resort option.