Having trouble merging these two datasets for a Spatial Analysis

Question

Whenever I try merging the datasets (TIGER/Line California data and CalEnviroscreen 4.0 dataset) the variables for CalEnviroscreen 4.0 show null values instead of the original values. This is an image of the output when I do the following:

import esda
import geopandas as gpd
import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
import seaborn as sns
from libpysal import io
from libpysal import weights
from scipy import stats

np.random.seed(0)



tracts_ca = gpd.read_file("data/tl_2020_06_tract/")

tracts_ca = tracts_ca.set_index("GEOID")

tracts_ca.shape



tracts_ca.columns



tracts_ca.head()



crs = "+proj=utm +zone=11 +ellps=WGS84 +datum=WGS84 +units=m +no_defs"

tracts_ca = tracts_ca.to_crs(crs)



df_calenviroscreen = pd.read_csv("data/calenviroscreen4.csv")

df_calenviroscreen.shape


df_calenviroscreen.columns


df_calenviroscreen.head()


tracts = tracts_ca.merge(df_calenviroscreen, left_index=True, right_index=True, how="left")
tracts.shape