Especially given that the very first paragraph of the article says that most vitamin supplements appear to be ineffective.
However, subsequently a meta-analysis (including that same paper) was published that found:
"Vitamin D [supplementation] was associated with significant reduction of cancer-related mortality compared with placebo [...]. Compared with placebo, Vitamin D was not associated with significant reduction of cancer incidence [...]".
https://www.tandfonline.com/doi/pdf/10.1080/20009666.2019.17...