The study cited in the video is like this
Many studies have linked consumption of aspartame to increased risk of some malignancies such as brain cancer, https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(05)62868-1/fulltext
Also non-Hodgkin lymphoma, multiple myeloma, and leukemia in men. https://academic.oup.com/ajcn/article/96/6/1249/4571428?login=true
As always, industries are trying to disprove the links between aspartame consumption and increased cancer risk. It is up to the consumers to decide whom they can trust.