While the proven Zacks Rank places an emphasis on earnings estimates and estimate revisions to find strong stocks, we also know that investors tend to develop their own individual strategies. With this in mind, we are always looking at value, growth, and momentum trends to discover great companies.Of these, perhaps no stock market trend is more popular than value investing, which is a strategy that has proven to be successful in all sorts of market environments. Value investors use tried-and-true metrics and fundamental analysis to find companies that they believe are undervalued at their current share price levels.Zacks has developed the innovative Style Scores system to highlight stocks with specific traits. For example, value investors will be interested in stocks with great grades in the "Value" category. When paired with a high Zacks Rank, "A" grades in the Value category are among the strongest value stocks on the market today.CVS Health (CVS) is a stock many investors are watching right now. CVS is currently sporting a Zacks Rank of #2 (Buy) and an A for Value. The stock holds a P/E ratio of 8.09, while its industry has an average P/E of 8.53. Over the past year, CVS's Forward P/E has been as high as 10.72 and as low as 7.23, with a median of 8.83.Investors should also note that CVS holds a PEG ratio of 1.45. This metric is used similarly to the famous P/E ratio, but the PEG ratio also takes into account the stock's expected earnings growth rate. CVS's industry has an average PEG of 1.69 right now. CVS's PEG has been as high as 1.63 and as low as 1.01, with a median of 1.41, all within the past year.We should also highlight that CVS has a P/B ratio of 1.16. The P/B is a method of comparing a stock's market value to its book value, which is defined as total assets minus total liabilities. This stock's P/B looks solid versus its industry's average P/B of 1.23. CVS's P/B has been as high as 1.58 and as low as 1.06, with a median of 1.27, over the past year.Finally, we should also recognize that CVS has a P/CF ratio of 6.29. This figure highlights a company's operating cash flow and can be used to find firms that are undervalued when considering their impressive cash outlook. This company's current P/CF looks solid when compared to its industry's average P/CF of 6.75. Within the past 12 months, CVS's P/CF has been as high as 9.27 and as low as 5.90, with a median of 7.24.These figures are just a handful of the metrics value investors tend to look at, but they help show that CVS Health is likely being undervalued right now. Considering this, as well as the strength of its earnings outlook, CVS feels like a great value stock at the moment.Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report CVS Health Corporation (CVS): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research