Pion is important in Nuclear Physics. Yukawa introduced pion as a mediator of nucleon-nucleon interaction in 1934 [1]. However, Nuclear Physics started by shell model with strong spin-orbit interaction in 1949 by Meyer and Jensen. The shell model is a phenomenological model and it has to be explained from more basic dynamics by explicitly using pion. The pion had not played the central role in nuclear physics until recent years. In this paper, we would like to discuss the recent development on the role of pion in nuclei.