Cumulative return is ending value divided by starting value, minus one. A 214% cumulative return sounds impressive until you learn it took eleven years, which is 10.9% annualised - a little under a passive index over the same stretch.
Two figures must accompany it to be meaningful: the period length, so it can be converted to annualised-return, and the worst drawdown along the way, so the path is visible. A 214% cumulative return with a 12% maximum drawdown and the same return with a 70% drawdown are entirely different products, and the cumulative number cannot tell them apart.
Be especially wary of cumulative figures on charts with a log scale omitted and deposits included. Adding capital raises the ending balance without earning a thing - see deposit-adjusted-return.
Related: annualised-return, deposit-adjusted-return, max-drawdown, equity-curve