Beta Cancri b

[1][2] First evidence for a planet around Beta Cancri was presented in 2008, when variations of the host star's radial velocity with an period of 673 days, but at that time an explanation to the radial velocity variations (such as a planet) wasn't presented.

In 2014, Lee et al. found further evidence for the planet's existence, finding a different period of 605.2 days.

After ruling out alternative explanations for the radial velocity variations, such as stellar variability, its existence could be confirmed.

[1] Beta Cancri b was discovered with doppler spectroscopy,[3] also known as the radial velocity method, which consists on observing small variations in the star's spectrum, which are radial velocity variations and happen because the planet is able to gravitationally pull its host star.

[5] It is a K-type giant with 70% more mass than the Sun[1] but a diameter 50 times larger.