Poisson CDF
The CDF of a Poisson distribution is right continuous.
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ListStepPlot[CDF[PoissonDistribution[17], Range[0, 35]], 
 PlotMarkers -> Automatic, Joined -> False, 
 PlotTheme -> {"Detailed", "Wide"}, ImageSize -> 550]Out[1]=

The CDF of a Poisson distribution is right continuous.

ListStepPlot[CDF[PoissonDistribution[17], Range[0, 35]], 
 PlotMarkers -> Automatic, Joined -> False, 
 PlotTheme -> {"Detailed", "Wide"}, ImageSize -> 550]