Learn French: Elle travaille efficacement tout en écoutant le podcast. - She works efficiently while listening to the podcast.

Both translate to "while listening", but adding tout before en strongly emphasizes that the two actions are happening at the exact same time. In this context, it also adds a slight feeling of concession, implying she is able to work efficiently despite the potential distraction of the podcast.

How exactly is the present participle écoutant formed here?

To form the present participle (the "-ing" form used with en), you take the present tense nous form of the verb, drop the -ons, and add -ant. So for écouter, nous écoutons becomes écoutant.

Why doesn't écoutant need a preposition like à before le podcast?

English uses "to listen to", but the French verb écouter already includes the "to" concept. It is a transitive verb that takes a direct object, so you simply say écoutant le podcast without adding any preposition.

Could I put the adverb efficacement before the verb, like we do in English with "efficiently works"?