I could not run the code, because several constants are missing (e.g. alpha1,beta1 etc.)
The error in your code is that you have not written the entire system of ODEs.
Something like the code below should work when completed.
If you share all the necessary info, I could try to run it and see if it works.
clear,clc
% Constants
a = 4.3*10^-1;
b = 2.17*10^-8;
p = 2*10^2;
g = 1*10^7;
m = 2*10^-2;
q = 3.4*10^-10;
r1 = 7.25*10^-15;
r2 = 6.9*10^-15;
r3L = 1.95*10^-12;
r3C = 1.95*10^-12;
k1 = 5*10^-7;
j = 1.245*10^-2;
k2 = 2.019*10^7;
Yinit = ones(1,5)*1.5*10^7;
[t,y]=ode45(@(t,y)TumorCells(t,y,a,b,p,g,m,q,r1,r2,r3L,r3C,k1,j,k2),[0 70],Yinit);
plot(t,y)
ylabel('Tumor (Cells)');
xlabel('Time(day)');
legend('untreated', 'CpG 1', 'CpG 2', 'CpG 3')
function dydt = TumorCells(t,y,a,b,p,g,m,q,r1,r2,r3L,r3C,k1,j,k2)
T = y(1);
E = y(2);
Th1 = y(3);
Treg = y(4);
DCL = y(5);
dTdt = a*T*(1-b*T)-(p*E*T)/(g+T);
dEdt = -m*E-q*E*T+r1*Th1*E*T-r2*Treg*E*T+(r3L*DCL+r3C*DCC)*((E*T)/(1+k1*T))+j*(T*E)/(k2+T);
dThqdt = % expression
dTregdt = % expression
dDCLdt = % expression
end
