Soft skills are different from hard skills (learned skills). These are personal attributes one needs to succeed in a workplace and are difficult to teach. Companies look for people who can become leaders that possess these skills and can effectively interact with others. They look for the qualities that show that an individual must get along well with all the people with whom they interact, including managers, co-workers, clients, vendors, customers, and anyone else they communicate with while on the job.
An instructive example of the difference made by soft skills is a mechanic. A mechanic is required to have an extensive repertoire of hard skills pertaining to the proper maintenance or repair of an engine. But a mechanic who does not have the soft skills of trustworthiness and approachability is not likely to be very highly regarded by their customers.
Similarly, a salesperson who may have an unrivaled and exhaustive knowledge of their market will find it difficult to close a deal and retain their clients if they lack the interpersonal skills and negotiation.