Both President Trump and the Republican party's separate tax proposals recommend the repeal of the federal estate tax. California State Senator Scott Wiener sponsored Senate Bill (SB)726 which would create a California estate tax in the event that the federal estate tax is repealed. SB726 This new California estate tax would appear to require a California resident to pay a California estate tax in an amount equal to the federal estate tax that would be repealed!
SB 726 was announced on February 21, 2017. Senator Wiener amended the bill on March 23, 2017 to seek a special election of California voters and to specifically amend the California Revenue Taxation Code to implement the provisions of SB 726. Senator Wiener indicates that the new estate tax is to be used to recapture funds for California schools, health, roads and public transportation.
As a bit of irony, California voters in 1982 prohibited any state inheritance or estate tax in Propositions 5 and 6. These propositions passed by votes of 61.5% and 64.49%. This was true even though the California estate tax was a "pick-up" tax that reduced the federal tax by the amount paid to California. In other words, the repeal of the California tax did not really provide any meaningful savings to California residents and shifted these funds to the federal government.
In any event, California shows a much greater willingness now to tax wealthier California residents. This was evidenced in 2012 when California voters approved the increase in the top marginal income tax rate for California residents to 13.3%. This "temporary" tax increase was just extended in 2016 with Proposition 55.