I stand in solidarity with the black lives matter movement.
It is not enough to stand in solidarity without accountability and actions towards change. Us, as mathematicians, we must continuously and actively work towards diversifying mathematics which has been historically (and continues to be) comprised mainly of white cishet men and we must acknowledge the racism present throughout mathematics. We must work towards ending institutional and systemic racism in our departments, work to promote and hire more underrepresented minorities and to encourage and support young mathematicians from underrepresented communities. This must be done by everyone; the burden must not be placed on underrepresented minorities. If you can, I'd also highly encourage donating to Mathematically gifted and black or The algebra project. Mathematics is for everyone.
If you don't have power in your department and/or don't have money to donate, you can check out this list or this list for ways you can help.
The scholar strike is a strike which happened on September 9-10 in US and Canada. It originated by a tweet of Dr. Anthea Butler who put out a call for a labour action for academics similar to the one put on by the WNBA and NBA. These days were chosen because of their proximity to Labour day and the start of the school year.
A program of talks can be found on the Canadian website:
• Scholar Strike Canada