R Markdown and Leaflet

library(leaflet)

## Warning: package 'leaflet' was built under R version 3.4.4

map <- leaflet() %>% 
  addTiles() %>%
  addMarkers(lat=19.5094224, lng=-99.1312807, 
             popup="CINVESTAV (Research institute, Mexico-City)")
map

library(maps)

## Warning: package 'maps' was built under R version 3.4.4

mapStates = map("state", fill = TRUE, plot = FALSE)
leaflet(data = mapStates) %>% addTiles() %>%
  addPolygons(fillColor = topo.colors(10, alpha = NULL), stroke = FALSE)