  An irreducible smooth representation of a $p$-adic group $G$ is said to be
distinguished with respect to a subgroup $H$ if it admits a non-trivial
$H$-invariant linear form. When $H$ is the fixed group of an involution on $G$
it is suggested by the works of Herv\'e Jacquet from the nineties that
distinction can be characterized in terms of the principle of functoriality. If
the involution is the Galois involution then a recent conjecture of Dipendra
Prasad predicts a formula for the dimension of the space of invariant linear
forms which once again involves base change. We will describe the proof of this
conjecture (in the generic case) for $SL(n)$ which is joint work with Dipendra
Prasad. Then we describe one more newly discovered connection between
distinction and base change which is that base change information appears in
the constant of proportionality between two natural invariant linear forms on a
distinguished representation. This latter result is for discrete series for
$GL(n)$ and is joint with Nadir Matringe. This paper is a report on the
author's talk in the International Colloquium on Arithmetic Geometry held in
January 2020 at TIFR Mumbai.
