CS Training Successes & Impact on CS Metrics Success/Results

I'm super curious to hear from those of you in a CS leadership role and those of you who have chosen a CS individual contributor role, what training you have received (internal to your company or from an outside source) that has had the greatest impact on your ability to produce considerable results in your as a CS Professional. If you're comfortable sharing the results and metrics that the training enabled you to move that would be really helpful as well. Thanks!