A short survey on $\delta$-ideal CR submanifolds

This paper surveys some of the known results on $\delta$-ideal CR submanifolds in complex space forms, the nearly K"{a}hler $6$-sphere and odd dimensional unit spheres. In addition, the relationship between $\delta$-ideal CR submanifolds and critical points of the $\lambda$-bienergy is mentioned. Some topics on variational problem for the $\lambda$-bienergy are also presented.