Every week on the Modern Retail Rundown, we cover the latest headlines from the retail world.

First is a look at the sudden departure of H&M’s chief executive officer, who cited the demanding nature of the job. Next, TikTok is reportedly testing a video feature that shows users similar products sold in TikTok Shop -- hinting at an increased focus on growing e-commerce. Finally, why Amazon’s advertising business continued to grow during the fourth quarter -- surging 27% year-over-year, to $14.7 billion.

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